XXX.—Notice of th e d is cov e ry of a n e w Fos s il An im al, form in g a lin k
b e tw e e n th e Ich th y os a u ru s a n d Crocod ile , toge th e r -w ith ge n e ral re m ark s
on th e Os te ology of th e Ich th y os a u ru s ;
from the Observations of H. T. De la BECHE, Esq. F.R.S. M.G.S.
AND
The Rev. W. D. CONYBEARE, F.RS. M.G.S.
DRAWN UP AND COMMUNICATED BY THE LATTER.
[Read April 8, 1821.]
I
N t h e cou r s e of a s er ies of ob s er va t ion s on t h e or ga n ic r em a in s
con t a in ed in t h e lia s in t h e vicin it y of Br is t ol, m y a t t en t ion wa s
p a r t icu la r ly a t t r a ct ed b y t h e n u m er ou s ver t eb r æ of ovip a r ou s
qu a d r u p ed s occu r r in g in t h a t for m a t ion . Of t h es e a con s id er a b le
p or t ion ob viou s ly b elon ged t o t h e Ich t h yos a u r u s ; t h e r em a in in g,
a n d la r ger d ivis ion , p r es en t ed ver t eb r a of for m s con s id er a b ly
d iffer in g fr om ea ch ot h er , b u t wh ich , fr om s om e gen er a l a n a logies ,
I wa s p er s u a d ed h a d a ll b elon ged t o d iffer en t p la ces in t h e
ver t eb r a l colu m n of a s in gle s p ecies ; a n d I ven t u r ed even t o p oin t
ou t t h os e p la ces , fr om a com p a r is on wit h t h os e of t h e cr ocod ile t o
wh ich t h ey b or e a s t r on g gen er a l r es em b la n ce, yet a t t h e s a m e t im e
com b in ed wit h s o m a n y m a t er ia l p oin t s of d iffer en ce, a s t o p r ove
t h a t t h e a n im a l fr om wh ich t h ey wer e d er ived m u s t h a ve
con s t it u t ed a s ep a r a t e gen u s .
At t h is p er iod , I wa s for t u n a t e en ou gh t o a s s ocia t e in m y r es ea r ch es a collea gu e equ a lly a b le a n d zea lou s , wh os e n a m e s t a n d s
at
VOL.
V.
4B
560
Mr. De la BECHE a n d Mr. CONYBEARE on
t h e h ea d of t h is p a p er . Th e n u m er ou s im p or t a n t a n d illu s t r a t ive
s p ecim en s wh ich h e p la ced a t m y d is p os a l, p r oved of m a t er ia l a id ,
a n d s t ill m or e s o h is gen er a l a cqu a in t a n ce wit h t h e s u b ject , of
wh ich I s u b s equ en t ly en joyed t h e fu lles t a d va n t a ge ; s o t h a t t h e
fa ct s n ow s u b m it t ed t o t h e S ociet y m u s t b e con s id er ed a s t h e fr u it
of in qu ir ies p r os ecu t ed b y u s in com m on .
A s k elet on of t h e a n im a l in qu es t ion , d eficien t on ly in t h e
b on es of t h e h ea d , p r es er ved in t h e well k n own collect ion of Col.
Bir ch , (wh o m os t lib er a lly a llowed u s t h e fu ll u s e of t h e ver y
va lu a b le m a t er ia ls h e p os s es s ed )* con fir m ed in a m os t s a t is fa ct or y
m a n n er m os t of m y p r eviou s con ject u r es , a n d en a b led u s t o a s s ign
t o it it s t r u e p la ce in t h e zoologica l or d er , a n d t o d es ign a t e it b y a n
a p p r op r ia t e n a m e. Th a t of Ple s ios a u ru s h a s b een ch os en , a s
exp r es s in g it s n ea r a p p r oa ch t o t h e or d er La cer t a .
Th e p oin t s of a n a logy b et ween t h e n ewly d is cover ed a n im a l a n d
t h e Ich t h yos a u r u s a r e s u fficien t ly n u m er ou s a n d im p or t a n t t o
evin ce t h e p r op r iet y of t h eir b ein g r efer r ed t o t h e s a m e gr ea t
n a t u r a l fa m ily, a fa m ily on ever y a ccou n t h igh ly d es er vin g a n
a t t en t ive exa m in a t ion , it s m em b er s b ein g n ot on ly u n k n own in t h e
r ecen t s t a t e, b u t p r es en t in g m a n y p ecu lia r it ies of gen er a l
s t r u ct u r e, of wh ich n o ot h er exa m p les h a d b een p r eviou s ly
ob s er ved ; a n d of t h a t m os t in t er es t in g d es cr ip t ion wh ich a ffor d s
in t er m ed ia t e for m s , a n d a s it wer e a t r a n s it ion b et ween d iffer en t
r a ces , a n d a d d s n ew lin k s t o t h e con n ect ed ch a in of or ga n ized
b ein gs . †
* I h a ve a ls o t o a ck n owled ge ou r ob liga t ion s on -s im ila r gr ou n d s t o Mr . Br igh t , D r .
D yer , Mes s r s . Miller , J oh n s on , Br a ik en r id ge, Cu m b er la n d , a n d Pa ge of Br is t ol.
† Wh en a llu d in g t o t h e r egu la r gr a d a t ion , a n d , a s it wer e, t h e lin k ed a n d
con ca t en a t ed s er ies of a n im a l for m s , we wou ld wis h ca r efu lly t o gu a r d a ga in s t t h e
a b s u r d a n d ext r a va ga n t a p p lica t ion wh ich h a s s om et im es b een m a d e of t h is
n ot ion . In t h e or igin a l for m a t ion of a n im a t ed b ein gs , t h e p la n evid en t ly t o b e
t r a ced t h r ou gh ou t is t h is . Th a t ever y p la ce
a n ew Fos s il An im al
561
Th e fa m ily, t h en , t o wh ich we wou ld t h u s r efer t h e a n im a ls a b ove
m en t ion ed , a n d t o wh ich fu t u r e r es ea r ch es m a y b e exp ect ed t o
a d d ot h er a n a logou s gen er a ,* m a y b e d es cr ib ed a s in clu d in g
a n im a ls a p p r oa ch in g m or e clos ely t o t h e S a u r ia n or Liza r d
fa m ily, a n d es p ecia lly t o t h e gen u s Cr ocod ile, t h a n t o a n y ot h er
r ecen t t yp e; yet r eced in g fr om it in m a n y im p or t a n t ch a r a ct er s ,
es p ecia lly in t h e for m of t h eir p a d d les , wh ich p os s es s a n
in t er m ed ia t e s t r u ct u r e b et ween t h e feet of qu a d r u p ed s a n d t h e
fin s † of fis h es , a n d h a ve b een well d is t in gu is h ed b y t h e a b ove
a p p r op r ia t e n a m e. As t h es e
ca p a b le of s u p p or t in g a n im a l life s h ou ld b e s o filled , a n d t h a t ever y p os s ib le m od e
of s u s t en a n ce s h ou ld b e t a k en a d va n t a ge of; h en ce ever y p os s ib le va r iet y of
s t r u ct u r e b eca m e n eces s a r y, m a n y of t h em s u ch a s t o in volve a t ot a l ch a n ge of
p a r t s , b u t ot h er s a ga in , s u ch a s r eq u ir ed n ot h in g b eyon d a m od ifica t ion of s im ila r
p a r t s , s ligh t in d eed in ext er n a l a p p ea r a n ce, yet im p or t a n t in s u b s er vin g t h e
p ecu lia r h a b it s a n d econ om y of t h e d iffer en t a n im a ls ; in t h es e ca s es t h e u n it y of
gen er a l d es ign wa s p r es er ved , wh ile t h e r eq u is it e p ecu lia r it y of or ga n is a t ion wa s
s u p er in d u ced ; n or ca n t h er e b e a n ywh er e fou n d a m or e s t r ik in g p r oof of t h e
in fin it e r ich es of cr ea t ive d es ign , or of t h e in fin it e wis d om wh ich gu id ed t h eir
a p p lica t ion . S om e p h ys iologis t s h owever (a n d La m a r ck is m or e es p ecia lly
cen s u r a b le on t h is a ccou n t ) h a ve m os t r id icu lou s ly im a gin ed t h a t t h e lin k s h en ce
a r is in g r ep r es en t r ea l t r a n s it ion s fr om on e b r a n ch t o a n ot h er of t h e a n im a l
k in gd om ; t h a t t h r ou gh a s er ies of s u ch lin k s , a n d b y m ea n s of t h e con s t a n t
t en d en cy of t h e vit a l flu id s , u r ged b y a n im a l a p p et en cies t o p er fect old or ga n s a n d
d evelop n ew on es , t h a t wh ich wa s on ce a p olyp u s b eca m e s u cces s ively a
m ollu s ca , a fis h , a q u a d r u p ed ; a n id ea s o m on s t r ou s , a n d s o com p let ely a t
va r ia n ce wit h t h e s t r u ct u r e of t h e p ecu lia r or ga n s con s id er ed in t h e d et a il (wh ich
is in t h e gr ea t m a jor it y of in s t a n ces s u ch t h a t n o con ceiva b le a p p et en cy cou ld
h a ve a n y con ceiva b le t en d en cy t o p r od u ce it ) a n d n o les s s o wit h t h e evid en t
p er m a n en cy of a ll a n im a l for m s , t h a t n ot h in g les s t h a n t h e cr ed u lit y of a m a t er ia l
p h ilos op h y cou ld h a ve b een b r ou gh t for a s in gle m om en t t o en t er t a in it —n ot h in g
les s t h a n it s b igot r y t o d efen d it .
* I d o n ot in t en d h er e t o in clu d e t h os e fos s il a n im a ls , wh ich a r e clea r ly on ly d is t in gu is h ed b y s p ecific ch a r a ct er s fr om t h e r ecen t cr ocod iles , b u t t h os e wh ich , t h ou gh
a p p r oxim a t in g m or e clos ely t o t h is t h a n t o a n y ot h er t yp e, a r e yet m a r k ed b y
gen er ic a n d es s en t ia l d iffer en ces .
† Th e a n a logy of t h es e p a d d les t o t h e fin s of fis h con s is t s in t h e n u m b er , n ot in
t h e for m of t h e join t s com p os in g t h em . In m a n y r es p ect s , a s will h er ea ft er b e
s h ewn , t h ey a p p r oa ch m os t n ea r ly t o t h e p a d d les of t h e t u r t le.
4 B2
562
Mr. De la BECHE a n d Mr. CONYBEARE on
a n im a ls a p p ea r u n qu es t ion a b ly t o h a ve lived , p r in cip a lly a t lea s t ,
in t h e s ea , a n d t o h a ve r eceived t h e p ecu lia r it ies of or ga n is a t ion t o
wh ich we h a ve a llu d ed , in or d er t o fit t h em for s u ch a n h a b it a t ion ,
t h e t er m En a lio-S a u ri m a y b e p r op os ed a s a cla s s ic a p p ella t ion t o
d en ot e t h e wh ole or d er . Of t h e gen er a com p os in g it , t h e Ich t h yos a u r u s r eced es m os t wid ely fr om t h e for m s of t h e liza r d fa m ily, in
or d er t o a p p r oa ch t h os e of fis h es ; b u t it is s t ill in com p a r a b ly
n ea r er t o t h e for m er ; a n d a ca r efu l s t u d y of it s os t eology p r es en t s ,
a s will p r es en t ly b e s een , a b ea u t ifu l s er ies of a n a logies wit h t h a t of
t h e cr ocod ile, in a ll t h e m os t es s en t ia l p a r t s .
Th e n ewly d is cover ed a n im a l, n a m ed on
t h a t a ccou n t
Ples ios a u r u s , a p p r oa ch es m u ch m or e n ea r ly t o t h e cr ocod ile,
for m in g in it s wh ole s t r u ct u r e, a lin k b et ween it a n d t h e
Ich t h yos a u r u s ; h en ce it a cqu ir es a h igh a n d p ecu lia r in t er es t , a s
a ffor d in g a m id d le t er m of com p a r is on , illu s t r a t in g t h e r ecip r oca l
r ela t ion s of b ot h , a n d oft en s h ewin g a r ea l con n exion b et ween
t h em , b y exh ib it in g a n in t er m ed ia t e gr a d a t ion of for m in p a r t s ,
wh ich wou ld , a t fir s t s igh t , a p p ea r t h e lea s t lik ely t o b e r econ ciled .
Of t h es e a n im a ls , t h e Ich t h yos a u r u s h a s a lr ea d y en ga ged a con s id er a b le s h a r e of a t t en t ion a m on g t h e s cien t ific p u b lic, h a vin g
b een illu s t r a t ed b y a wr it er wh os e n a m e s t a n d s d es er ved ly h igh
a m on g t h e com p a r a t ive a n a t om is t s of t h is cou n t r y. Yet , s in ce t h e
m a t er ia ls fr om wh ich h is d es cr ip t ion s wer e d r a wn u p ca m e on ly
in t o h is p os s es s ion gr a d u a lly, a n d wer e wit h a p r a is e-wor t h y
r ea d in es s com m u n ica t ed in s t a n t ly t o t h e p u b lic, t h e cir cu m s t a n ces
of t h e ca s e r en d er ed it im p os s ib le t o a t t em p t a r egu la r a n d
con n ect ed view of t h e wh ole os t eology of t h is a n im a l, a n d a s er ies
of d et a ch ed es s a ys on s u ch in d ivid u a l p oin t s of it s s t r u ct u r e a s t h e
s p ecim en s h a p p en ed t o p r es en t , wa s a ll t h a t wa s p r a ct ica b le; h en ce
m a n y of t h e m os t im p or t a n t p a r t s of t h e s k elet on , t h e wh ole
os t eology
of
th e
h ea d
for
a n ew Fos s il An im al
563
in s t a n ce, ca n n ot b e s a id a s yet t o h a ve b een in a n y d egr ee
elu cid a t ed ; t h e a n a logies b y wh ich it s p la ce in t h e n a t u r a l k in gd om
m u s t b e d et er m in ed , t h ou gh a b ly p oin t ed ou t , a r e fa r fr om h a vin g
b een fu lly u n fold ed , a n d a p r ecis e a n a t om ica l d es cr ip t ion of it s
gen er a l s t r u ct u r e r em a in s a d es id er a t u m .
Th e gr ea t s u b s equ en t a ccu m u la t ion of m a t er ia ls , wh ich m u s t b e
d ou b t les s in a gr ea t m ea s u r e a t t r ib u t ed t o t h e r es ea r ch es a b ove
a llu d ed t o, a n d m or e es p ecia lly t h e n u m er ou s s p ecim en s con t a in ed
in t h e m a n y collect ion s of t h is n eigh b ou r h ood (Br is t ol) a n d in t h a t
of Mr . De la Bech e, h a ve a ffor d ed m e, t h r ou gh t h e a b le a s s is t a n ce
of t h a t gen t lem a n , t h e m ea n s of fillin g u p t h e m os t m a t er ia l of t h e
ch a s m s in ou r in for m a t ion on t h e s u b ject s wh ich I h a ve
m en t ion ed ; a n d s in ce t h e p oin t s d et er m in ed a r e a t on ce in
t h em s elves of con s id er a b le im p or t a n ce, a n d p r om is e, fr om t h e
a n a logies a b ove s t a t ed , t o a ffor d con s id er a b le a s s is t a n ce in
p r os ecu t in g ou r fa r t h er ob s er va t ion s on t h e n ewly d is cover ed
a n im a l, we s h a ll p r efa ce t h e d et a ils con cer n in g it , wh ich we a r e
a b ou t t o s u b m it t o t h e S ociet y, b y a gen er a l a n d com p a r a t ive view
of t h e os t eology of t h e Ich t h yos a u r u s .
ICHTHYOS AURUS .
Ge n e ra l ch a ra cte rs . A m a r in e qu a d r u p ed , n ea r ly r es em b lin g t h e
cr ocod ile, in t h e os t eology of it s h ea d , a n d it s m od e of d en t it ion .
Ver t eb r a : h a vin g b ot h fa ces of t h eir b od y d eep ly con ca ve a s in
fis h es . E xt r em it ies h a vin g n o d is t in ct r a d iu s a n d u ln a , b u t t h e
h u m er u s im m ed ia t ely s u p p or t in g a ver y n u m er ou s s er ies of s m a ll
p olygon a l b on es , for m in g a ver y flexib le p a d d le. An t er ior
ext r em it ies m u ch la r ger t h a n t h e p os t er ior .
We h a ve r et a in ed in t h es e ob s er va t ion s t h e n a m e Ich t h yos a u r u s ,
or igin a lly a p p lied t o t h is a n im a l b y Mr . Kön ig of t h e Br it is h
Mu s eu m , feelin g con vin ced t h a t on a fu ll a n d ca r efu l r eview of it s
564
Mr. De la BECHE a n d Mr. CONYBEARE on
wh ole s t r u ct u r e, it will n ot b e fou n d t o p os s es s a n a logies
s u fficien t ly n u m er ou s or s t r on g wit h t h e p ecu lia r or ga n is a t ion of
t h e Pr ot eu s t o a u t h or is e t h e ch a n ge of t h is a p p ella t ion in t o
Pr ot eos a u r u s , a s s u b s equ en t ly p r op os ed .
Pa rticu la r Ob s e rv a tion s .
Os te ology of th e He a d .
a . Te e th .* Th es e b ea r a n ea r r es em b la n ce in for m t o t h os e of t h e
cr ocod ile; a n d t h e m od e of d en t it ion b y t h e you n g t oot h gr owin g u p
in t h e in t er ior of t h e ca vit y of t h e old on e, a n d wh en m a t u r ed ,
s p lit t in g a n d ca u s in g it t o fa ll, is exa ct ly s im ila r .
Th e t eet h a r e m or e n u m er ou s t h a n in t h e cr ocod ile ; t h er e
ca n n ot b e les s t h a n 3 0 on a s id e in eit h er ja w: b u t fr om t h eir
ir r egu la r gr owt h , t h eir p a r t ia l con cea lm en t in t h e s t on e, a n d
d ifficu lt y of fin d in g com p let e ja ws , t h ey h a ve n ot yet b een
a ccu r a t ely n u m b er ed . Th ey a r e p la ced in a lon g s u lcu s , for m ed in
t h e m a xilla r y a n d in t er m a xilla r y b on es , lik e t h a t in t h e ja w b on es
of s om e fis h es , n ot in s ep a r a t e a lveoli, a s in t h e cr ocod ile.
b . Low e r J a w s . In or d er t o d em on s t r a t e t h e clos e r ela t ion
b et ween t h e Ich t h yos a u r u s a n d t h e la cer t a fa m ily, it is
n eces s a r y t o p r em is e, t h a t t h e lower ja w in t h a t or d er , in s t ea d
of h a vin g, lik e ot h er q u a d r u p ed s , a s in gle b on e on eit h er s id e,
exh ib it s n o les s t h a n s ix of t h es e ; on e ca lled t h e d en t a l,
wh ich ca r r ies t h e t eet h , for m s t h e wh ole a n t er ior ext r em it y of
t h e ja w, a n d con t in u es t o cover t h e
* F r om t h e d iffer en t for m s of t h e t eet h a lon e, t h r ee s p ecies a t lea s t of t h e
Ich t h yos a u r u s m a y b e a s cer t a in ed ; b u t t h ey d iffer on ly in ver y s ligh t p oin t s , a n d
n ot in a n y t h a t ver y m a t er ia lly a ffect t h e gen er a l for m a n d s t r u ct u r e of p a r t s t o
wh ich it is ou r in t en t ion t o con fin e ou r s elves in t h e p r es en t p a p er . H er ea ft er wep r op os e a fu r t h er com m u n ica t ion on t h is s u b ject .
a n ew Fos s il An im al
565
u p p er p or t ion , a n d t o la p over t h e ext er ior ; t h e r es t of t h e ou t er
fa ce is for m ed , in t h e p os t er ior p a r t , b y a s econ d b on e, t h e
cor on oid ; t h e b ot t om b y a t h ir d , t h e a n gu la r ; a n d t h e in n er fa ce b y
a fou r t h , t h e op er cu la r ; in a d d it ion t o t h es e fou r b on es , t h e
a r t icu la r , wh ich is p la ced a t t h e p os t er ior ext r em it y for t h e p u r p os e
wh ich it s n a m e d en ot es , a n d a s m a ll cr es cen t -s h a p ed b on e, wh ich
s om et im es for m s t h e cor on oid p r oces s , com p let e t h e s t a t ed
n u m b er .
Of t h es e b on es , we h a ve s u cceed ed in d em on s t r a t in g t h e five
fir s t
on
th e
Ich t h yos a u r u s ,
occu p yin g
s it u a t ion s
clos ely
cor r es p on d in g t o t h os e wh ich t h ey p os s es s in t h e cr ocod ile. Th e
cr es cen t -s h a p ed b on e is t h e on ly on e of t h e s er ies wh ich we h a ve
n ot yet d et ect ed ; a n d t h is p r ob a b ly a r is es fr om ou r n ever h a vin g
s een t h e p a r t of t h e ja w in wh ich it occu r s fa ir ly exp os ed .
Alm os t t h e on ly d iffer en ces fr om t h e lower ja w of t h e cr ocod ile
a r e, 1 s t , t h e a p p a r en t a b s en ce of t h e ova l h ole* ju s t b eh in d t h e
t er m in a t ion of t h e d en t a l b on e, wh ich ch a r a ct er is es t h e la t t er ,
b u t wh ich is h owever n ot t o b e fou n d in ot h er s of t h e la cer t a
fa m ily ; a n d , 2 d ly, wh ich is m or e im p or t a n t , t h a t t h e b on es a r e
n ot con n ect ed b y com m on b u t s qu a m ou s s u t u r es , for m in g p la t es
fold in g over on e a n ot h er , a s in fis h es . ‡ Th is s t r u ct u r e, wh ich
com b in es
* In on e b ea u t ifu lly p er fect s p ecim en of Ich t h yos a u r u s , b elon gin g t o Mr . d e la
Bech e, s u lcu s com m u n ica t in g wit h a s m a ll for a m en m a y b e s een in a s im ila r
s it u a t ion . We h a ve n ot h owever t r a ced it a s yet in ot h er s ; b u t it is s o s it u a t ed a s t o
b e r ea d ily con cea led , b y b ein g filled u p wit h t h e s t on y in cr u s t a t ion .
‡
Th is over la p p in g m od e of a p p lica t ion , or a s it is t ech n ica lly t er m ed , s q u a m ou s
s u t u r e, occu r s a ls o in m os t of t h e b on es of t h e h ea d ; s in ce b y t h e a ccid en t a l
r em ova l of p or t ion s of t h e ext er n a l b on es , m ot e or les s of t h e in t er n a l, a ga in s t
wh ich t h ey a r c in con s eq u en ce of t h is s t r u ct u r e a p p lied , is oft en exh ib it ed in
d iffer en t s p ecim en s , a cor r ect id ea of t h eir ou t lin e ca n on ly b e ob t a in ed b y t h e
ca r efu l colla t ion of s ever a l s u ch s p ecim en s in t h eir or d in a r y s t a t e of p r es er va t ion ;
a n d a s in gle on e ca n on ly b e r elied u p on wh er e it a p p ea r s t o b e u n d ou b t ed ly
p er fect a n d u n m u t ila t ed , a cir cu m s t a n ce wh ich it r eq u ir es s om e p r a ct ice t o
a s cer t a in .
Th e s u t u r es of s om e of t h e b on es (t h os e p a r t icu la r ly of t h e or b it s ) a r e
s in gu la r ly
566
566
Mr. De la BECHE a n d Mr. CONYBEARE on
t h e gr ea t es t s olid it y a n d s t r en gt h wit h t h e lea s t weigh t of b on e, is
a d m ir a b ly ca lcu la t ed a t on ce t o in cr ea s e t h e b u oya n cy of t h e
a n im a l, a n d t o en a b le it t o fa ce t h e wa ves of a n a git a t ed ocea n , a n d
h a s d ou b t les s ly b een given t o it t o fit it for it s m a r in e a b od e.
Th e gen er a l for m of t h e ja w d iffer s fr om t h a t of t h e cr ocod ile in
b ein g m u ch m or e len gt h en ed a n d a cu t ely a n gu la r ; it s t er m in a t ion
is in d eed a lm os t a s s h a r p a s t h e b ea k of a b ir d . ‡
Th e a ccom p a n yin g figu r es (p la t e 4 0 , fig. 1 t o 1 0 ) will exp la in t h e
for m s a n d a r r a n gem en t of t h es e b on es b et t er t h a n a n y ver b a l
d es cr ip t ion . In or d er t o fa cilit a t e com p a r is on wit h t h e a n a logou s
b on es in t h e cr ocod ile, we h a ve em p loyed t h e s a m e let t er s wit h
wh ich M. Cu vier h a s m a r k ed t h e h ea d of t h a t a n im a l, in h is m em oir on t h e fos s il r em a in s of ovip a r ou s qu a d r u p ed s : †
viz. u ,
d en t a l ; x , cor on oid ; -v , a n gu la r ; , op er cu la r ; y, a r t icu la r .
Th e a p p ea r a n ce a n d r a n ge of t h e d en t a l, cor on oid , a n d a n gu la r
b on es on t h e ou t er fa ce of t h e ja w, a r e s h ewn in t h e s id e view of
t h e h ea d (Fig. 9 . p la t e 4 0 .)
Th e view of t h e lower ja w, a s s een fr om b e n e a th (fig. 1 0 , p la t e
4 0 ) exh ib it s t h e cou r s e of t h es e b on es a n d t h e op er cu la r
t h r ou gh ou t t h e ja w. Th e t r a n s ver s e s ect ion s n u m b er ed fr om on e
t o eigh t (p la t e 4 0 ), t h e p os it ion of wh ich is in d ica t ed b y t h e
d ot t ed lin es in t h e s id e of t h e h ea d , fu lly elu cid a t e t h e for m of
t h e s ever a l b on es
a d a p t ed for s t r en gt h } b ein g p a r t ly s q u a m ou s a n d p a r t ly d ovet a iled , s o t h a t on e
b on e is p a r t ly in s er t ed in t o t h e ot h er b y a s or t of a n gu la r p r oces s , on eit h er s id e of
wh ich t h ey over la p ea ch ot h er r ecip r oca lly. O n t h es e p oin t s we p r op os e, in a
fu t u r e com m u n ica t ion , t o s p ea k m or e in d et a il.
‡ S p ecim en s exh ib it in g t h e t er m in a t ion of t h e ja w in a n u n m u lila t ed con d it ion a r e
ver y r a r e ; we a r e in d eb t ed t o t h e k in d n es s of Mr . Miller for on e wh ich d is p la ys
t h a t of b ot h ja ws in a p er fect m a n n er .
† Rech er ch es
s u r les os s em en s fos s iles . Tem e 4 ..
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567
a n d t h e ch a n ges t h ey u n d er go in d iffer en t p a r t s of t h e ja w, fr om it s
a n t er ior t o it s p os t er ior ext r em it y, a n d a ls o t h e m a n n er of t h eir
a p p lica t ion t o ea ch ot h er .
B on e s of th e u p p e r p a rt of th e He a d .
Th es e h a ve t h e s a m e m a r k ed coin cid en ce wit h t h os e of t h e
cr ocod ile wh ich d is t in gu is h es t h e b on es of t h e lower ja w; t h ey a r e
s h ewn in t h e a ccom p a n yin g figu r es (p i. 4 0 ) fig. 9 ,1 1 , 1 2 , m a r k ed b y
t h e let t er s em p loyed b y M. Cu vier . S in ce t o d es cr ib e t h em a t len gt h
wou ld b e gen er a lly t o r ep ea t t h e wor d s of t h a t a u t h or , in t r ea t in g of
t h e s t r u ct u r e of t h a t a n im a l (t h e cr ocod ile), we s h a ll con fin e
ou r s elves t o a r a p id s k et ch , n ot icin g p r in cip a lly t h e p ecu lia r it ies of
con figu r a t ion b y wh ich t h e Ich t h yos a u r u s d iffer s fr om t h is t yp e,
m os t of wh ich a r is e fr om t h e a d a p t a t ion of t h e p a r t s t o t h e n a r r ow
a n d elon ga t ed con t ou r of t h e wh ole. Th e eye a ls o is r a t h er lower
p la ced t h a n in t h e cr ocod ile, t h e b ot t om of t h e or b it b ein g n ea r ly
on a level wit h t h e lin e of t h e op en in g of t h e ja ws ; t h is p r od u ces
s om e ver y s ligh t ch a n ges in t h e for m of t h e a d ja cen t b on es ; a n d
p er h a p s a s t ill m or e im p or t a n t d evia t ion occu r s in t h e p la ce of t h e
n os t r ils ; b u t t h is p oin t s t ill r em a in s in volved in s om e d egr ee of
ob s cu r it y.
We s h a ll fir s t con s id er t h os e b on es wh ich a p p ea r on t h e s id es
a n d in n er p a r t of t h e m ou t h , a s exh ib it ed in figu r es 9 , 1 1 , a n d 1 2 ,
p la t e 4 0 . a n d in t h e t r a n s ver s e s ect ion fig. 3 , of t h e s a m e p la t e.
Th e gen er a l ou t lin e of t h e u p p er , lik e t h a t of t h e lower ja w, is
m u ch m or e p oin t ed t h a n in a n y s p ecies of cr ocod ile ; it s t er m in a t ion r es em b les t h a t of t h e p or p ois e, t h e b on es of t h e op p os it e
s id es op en in g a t t h e en d s o a s t o for m a n a r r ow a n gu la r s lit ; t h is
s lit r equ ir es a n a t t en t ive exa m in a t ion fr om t h e d ou b t s t h a t h a ve
a r is en
VOL.
V.
4c
568
Mr. De la BECHE a n d Mr. CONYBEARE on
con cer n in g t h e p la ce of t h e n os t r il in t h is a n im a l; t h e t wo op en in gs
gen er a lly t o b e t r a ced in fr on t of t h e or b it s wer e a t fir s t t h ou gh t t o
h a ve d is ch a r ged t h is fu n ct ion , b u t S ir E ver a r d Hom e, h a vin g s u b s equ en t ly exa m in ed a s p ecim en in wh ich t h es e a p er t u r es wer e
ext er n a lly clos ed , wa s in d u ced t o r et r a ct t h is op in ion ; a n d h a vin g
ob s er ved t h a t a p a s s a ge s u p p os ed t o for m t h e n a s a l ca n a l
con t in u ed t o t h e for e en d of t h e s n ou t , h e in d ica t ed t h e p r op r iet y of
look in g for t h e n os t r il in t h a t p a r t , a s in t h e cr ocod ile. Th e
exa m in a t ion of a s p ecim en , in wh ich t h e ext r em it y of t h e s n ou t is
p r es er ved in a n en t ir e a n d u n a lt er ed for m , en a b les u s t o d et er m in e
p os it ively t h a t t h e ca n a l in qu es t ion t er m in a t es in t h e n a r r ow s lit
a b ove d es cr ib ed , a n d t h a t t h er e is n o ot h er op en in g wh a t ever in
t h is p a r t . We s t ill h owever feel gr ea t h es it a t ion in con s id er in g t h is
a s t h e t r u e n os t r il, s in ce it is s o m in u t e a s t o b e ou t of a ll
p r op or t ion wit h t h e s ize of t h e a n im a l, a n d we ca n n ot feel qu it e
s a t is fied t h a t s om e for ced a n d fa ls e p os it ion of t h e b on es in t h e
s in gle s k u ll a llu d ed t o m a y n ot h a ve cover ed u n n a t u r a lly t h e
op en in gs b efor e t h e or b it , a t fir s t s u p p os ed t o b e n os t r ils ; s in ce in
ever y ot h er s p ecim en we h a ve exa m in ed , a m ou n t in g t o n ea r ly
t wen t y, t h ey a p p ea r t o b e well d efin ed a n d p er fect ly op en .
Th e in t er m a xilla r y b on es , a , a , r u n m u ch fa r t h er b a ck t h a n in
t h e cr ocod ile; a va r ia t ion p a r t ly a r is in g fr om t h e p r olon ged for m
of t h e s n ou t . Owin g t o t h eir over lyin g t h e m a xilla r y b on es a lon g
t h e lin e of t h eir ju n ct ion , it is oft en d ifficu lt t o d is t in gu is h t h em ,
es p ecia lly a s t h ey lea ve on ly a ver y s m a ll p or t ion of t h e la t t er
exp os ed on t h e ou t er s id e of t h e ja w ; t h ey h a ve a ls o a n over lyin g
a p p lica t ion a ga in s t t h e n a s a l b on es . Th es e a n d t h e m a xilla r y
b on es , b , b , fu r t h er d iffer fr om t h os e of t h e cr ocod ile (in com m on
wit h t h os e of t h e lower ja w), b y ca r r yin g t h e t eet h in a n op en
s u lcu s in s t ea d of s ep a r a t e a lveoli. Th e m a xilla r y b on es a r e a ls o
m or e con fin ed t o
a n ew Fos s il An im al
569
t h e b a ck p a r t of t h e ja w, a n d b r oa d er a n d fla t t er a t t h eir p os t er ior
ext r em it y, wh er e t h ey u n d er lie t h e or b it , a n d a r e s ligh t ly cu r ved t o
fit t h em for t h eir s it u a t ion . In t h e r oof of t h e m ou t h , t h e m a xilla r y
b on es , r eced in g fr om ea ch ot h er a s t h ey a d va n ce t owa r d s t h e
p os t er ior p a r t s , exh ib it , (a s s een in fig. 3 & 1 2 , p la t e 4 0 .) t h e
p a la t a ls , e , e , wh ich clos ely r es em b le t h os e of t h e cr ocod ile, b u t a r e
s t ill lon ger a n d n a r r ower .
Bet ween t h e p os t er ior t er m in a t ion s of t h e p a la t a l a n d m a xilla r y
b on es , is a n op en in g, a s in cr ocod iles , b u t m or e elon ga t ed a n d n a r r ow ; t h is op en in g in t h e cr ocod ile is s u r r ou n d ed on t h e p os t er ior
s id e b y t h e p t er ygoid p r oces s es , f,f, a n d a p ecu lia r b on e, d , wh ich
m a y b e con s id er ed a s a n ext er n a l p t er ygoid p r oces s in t er ven in g b et ween t h e p r eced in g a n d t h e m a xilla r y b on e on eit h er s id e. Th is
s t r u ct u r e, con s id er ed I b elieve, a s p ecu lia r t o t h es e a n im a ls , is a ls o
t o b e ob s er ved in t h e Ich t h yos a u r u s , wh er e t h e p ecu lia r b on e, tf,
will b e s een r es t in g a ga in s t t h e in s id e of t h e t er m in a t ion of t h e
m a xilla r y, a n d ext en d in g in a lon g p r oces s t o t h e h in d er ext r em it y
of t h e h ea d . Of t h e p t er ygoid p r oces s es f,f, t r a ces on ly h a ve b een a s
yet d is cover ed , t oo m u ch b r ok en a n d d is t or t ed for r ep r es en t a t ion ^
b u t qu it e s u fficien t t o s h ew t h a t t h ey n ea r ly a gr eed wit h t h os e of
t h e cr ocod ile.
Ha vin g t h u s d es cr ib ed s u ch of t h e b on es a s occu r in t h e r oof of
t h e m ou t h , we p r oceed t o t h os e wh ich occu p y t h e ext er n a l p a r t of
t h e fa ce. Th e n a s a l b on es , k , k , a r e p la ced a s in t h e cr ocod ile.
Bet ween t h e n a s a l b on es a n d t h e p os t er ior ext r em it y of t h e m a xilla r y b on es , b , b , lie t h e la cr ym a l b on es , i, i; t h es e for m t h e a n t er ior
m a r gin of t h e or b it in it s lower p a r t ; in fr on t of t h es e b on es a r e
p la ced t h e ova l op en in gs b efor e a llu d ed t o a s is gen er a lly t o b e ob s er ved in a ll t h e s k u lls of t h is a n im a l yet fou n d , wit h a s in gle
excep t ion , wh ich a t fir s t (a n d a s we s t ill t h in k wit h m u ch
p r ob a b ilit y),
4C2
570
570
Mr. De la BECHE a n d Mr. CONYBEARE on
wer e s u p p os ed t o h a ve b een t h e n os t r ils . We h a ve a lr ea d y s t a t ed
ou r r ea s on s for d ou b t in g wh et h er t h e con t r a r y evid en ce, a r is in g
fr om t h e s in gle s p ecim en in wh ich t h es e a p er t u r es a p p ea r ed t o b e
clos ed
ext er n a lly, wa s
qu it e s u fficien t
t o in va lid a t e t h is
s u p p os it ion . If h owever it s h ou ld even t u a lly b e p r oved t h a t t h es e
op en in gs a r e a ct u a lly clos ed in p er fect s p ecim en s , wh ich , a lt h ou gh
we h a ve yet fa iled in t r a cin g t h e fa ct , m a y n ever t h eles s n ot
im p os s ib ly t a k e p la ce, in con s equ en ce of t h e p r olon ga t ion s of t h e
in t er m a xilla r y a n d a n t er ior fr on t a l b on es fold in g over t h em ; (s in ce
t h e com m on m u t ila t ion of t h e ext r em it ies of t h os e b on es m igh t
cer t a in ly a ccou n t for t h e p r es en t exp os u r e of t h es e op en in gs : *)—
in t h a t ca s e t h e n a r r ow s lit a t t h e for e en d of t h e s n ou t m u s t b e t h e
t r u e n os t r il, a n d t h es e ova l for a m in a m u s t b e t h e op en in gs of t h e
la cr ym a l in t o t h e in t er ior of t h e n a s a l ca n a l, exp os ed b y t h is
a ccid en t a l r em ova l of t h eir ext er n a l cover in g ; a s u p p os it ion wh ich
will a gr ee ver y well wit h t h eir p la ce in fr on t of t h eir la cr ym a l b on es ;
t h ey a r e r ep r es en t ed b y d ot t ed s p a ces in t h e a ccom p a n yin g figu r es .
We h a ve n ow d es cr ib ed a ll t h e b on es of t h a t p a r t of t h e h ea d
wh ich is a n t er ior t o t h e or b it , a n d for m s t h e s n ou t of t h e a n im a l.
Th e fr on t a l p a r t of t h e h ea d con s is t s of five d is t in ct b on es ; t h e
m id d le fr on t a l, H, wh ich ext en d s b et ween t h e or b it s , t h e a n t er ior
fr on t a ls , b , b , wh ich for m t h e u p p er a n t er ior p or t ion s of t h e or b it ,
a n d t h e t wo p os t er ior fr on t a ls , h ’, h ’, wh ich b y t h eir p os t -or b it a l
p r oces s es h ", h ", for m t h e u p p er a n d p os t er ior m a r gin of t h e or b it ,
a n d com p let e it b y u n it in g wit h t h e ju ga ls , c, c, wh ich for m it s
lower p a r t .
* S in ce t h is p a p er wen t t o p r es s we h a r e s een s p ecim en s wh ich d ecid e t h a t t h is
a p er t u r e wa s a ls o p er for a t ed t h r ou gh t h e en d of t h e in t er m a xilla r y b on e, a n d
con s eq u en t ly m u s t h a ve b een op en ext er n a lly ; t h e n eces s a r y con clu s ion is , t h a t
t h e a p p ea r a n ces in t h e s in gle s k u ll, d es cr ib ed b y S ir E ver a r d H om e, m os t h a ve
b een d ecep t ive, a n d t h a t t h e on ly ob ject ion t o con s id er in g t h es e a p er t u r es a s t h e
n os t r ils is r em oved .
a n ew Fos s il An im al
571
Th e on ly d iffer en ce in t h es e r es p ect s is , t h a t t h e p os t -or b it a l p r oces s b ",b ", in t h e Ich t h yos a u r u s , d oes n ot , a s in t h e cr ocod ile, b en d
in wa r d s , b u t m eet s t h e ju ga l c, in t h e lin e of t h e gen er a l cu r va t u r e
of t h is p a r t of t h e fa ce, s o t h a t t h e m a r gin of t h e or b it is n ea r ly of
t h e s a m e cu r va t u r e t h r ou gh ou t , a n d t h e ju ga l b on e c, in
con s equ en ce of t h e lower s it u a t ion of t h e eye, is m u ch r ed u ced in
s ize.
We h a ve n ow a r r ived a t t h e b on es wh ich a r e b eh in d t h e or b it s
a n d over t h e s u m m it of t h e cr a n iu m , cor r es p on d in g in s it u a t ion t o
t h e p a r iet a l b on es of ot h er qu a d r u p ed s .
Her e a ga in t h e cr ocod ile h a s a p ecu lia r s t r u ct u r e, t h is p a r t of t h e
h ea d b ein g d is t in gu is h ed b y t wo la r ge ova l op en in gs n ot u n lik e
t h os e of t h e or b it s , b u t r a t h er s m a ller , wh ich m a y b e ca lled fr om
t h eir s it u a t ion t h e s u p er -p a r iet a l ca vit ies . Bet ween t h es e ca vit ies is
t h e b on e m , a n s wer in g t o t h e s in gle p a r iet a l of r u m in a n t s , t h e
b on es m a r k ed n , n , con s id er ed a s a n s wer in g t o p or t ion s of t h e
t em p or a l b on es for m t h eir p os t er ior a n gles , a n d b y u n it in g wit h t h e
la t er a l fr on t a ls h ’, h ’, com p let e t h e en clos u r e.
All t h es e s t r on gly m a r k ed ch a r a ct er s occu r wit h ou t a n y m a t er ia l
d evia t ion in t h e Ich t h yos a u r u s .
Th e la s t b on es of t h e h ea d we s h a ll d es cr ib e a r e t h os e wh ich
in t er p os e b et ween t h e ju ga l c, a n d t h e la s t m en t ion ed b on e(n ), a n d
wh ich t oget h er wit h it , a r e con s id er ed a s m a k in g u p t h e r em a in d er
of t h e t em p or a l ; t h e fir s t of t h es e, o, wh ich b ea r s a t it s in fer ior a n d
h in d er ext r em it y t h e con d yle for a r t icu la t ion wit h t h e lower ja w,
m a y b e ob s er ved p la ced in t h e Ich t h yos a u r u s , a s in t h e cr ocod ile,,
n a m ely, ext en d in g fr om t h e la t er a l fr on t a l b ’, t owa r d s n , t o a p r oces s of wh ich it join s ; p is in t er p os ed b et ween t h is a n d t h e ju ga l
b on e c, a n d t h u s com p let es t h e en clos u r e of t h e t em p or a l fos s a ,
wh ich s eem s t o h a ve b een n a r r ow in t h is a n im a l.
572
Mr. De la BECHE a n d Mr. CONYBEARE on
We h a ve n ot yet b een for t u n a t e en ou gh t o fin d a s p ecim en wh ich
wou ld p er m it u s t o exa m in e t h e b on es of t h e h in d er a n d in fer ior
p or t ion s of t h e s k u ll ; b u t t h e os t eologica l d et a ils we h a ve a lr ea d y
s u b m it t ed m u s t b e con s id er ed a s p la cin g in t h e fu lles t ligh t of d em on s t r a t ion t h e n ea r a llia n ce of t h is a n im a l, a n d it s a lm os t
id en t ica l s t r u ct u r e, wit h t h e cr ocod ile.
Th e eye of t h is a n im a l h a s it s s cler ot ica , a s is well k n own , com p os ed of a lon g or r a t h er s ca ly s u b s t a n ce s u b d ivid ed in t o t h ir t een
p la t es . I h a ve n ow b efor e m e t h e eye of a m id d le s ized liza r d fr om
Ger m a n y, wh ich h a s a s t r u ct u r e exa ct ly s im ila r , excep t in g t h a t t h e
p la t es a r e m or e n u m er ou s .* Th e ch a m elion , igu a n a , a n d t u p in a m b is , h a ve s im ila r os s eou s la m in æ , a s h a s t h e t or t ois e, b u t in t h is
la t t er a n im a l t h ey for m , a s in b ir d s , t h e a n t er ior d is k .
A fos s il a n im a l fou n d a t Milen h a r t , n ea r Det t in gen , in t h e d is t r ict
of Ma n h eim , a n d d es cr ib ed in t h e Mu n ich t r a n s a ct ion s u n d er t h e
n a m e La cer t a giga n t ea , wh ich clos ely r es em b les , if it b e n ot id en t ica l wit h , t h e Mæ s t r ich t a n im a l, h a s evid en t ly t h e s a m e s t r u ct u r e.
Ve rte b ra .
Alt h ou gh t h r ou gh ou t t h e b on es of t h e h ea d , s o clos e a n a n a logy
h a s b een fou n d t o p r eva il b et ween t h e Ich t h yos a u r u s a n d
Cr ocod ile, t h e ver t eb r a ; a r e wid ely d iffer en t , a n d m u ch m or e
a n a logou s t o t h os e of fis h es , h a vin g, lik e t h em , in con s equ en ce of
t h e d ou b le, con ca ve for m of t h eir b od ies , t h e in t er -ver t eb r a l join t
d eep ly cu p p ed
*Th is wa s p oin t ed ou t t o m e b y Mr , Miller , t o wh os e a s s is t a n ce I h a ve ot h er wis e
b een m u ch in d eb t ed , a n d wh o b y t h e s cien t ific s p ir it a n d u n wea r ied p er s ever a n ce
wh ich h e h a s a p p lied t o t h e illu s t r a t ion of t h e com p a r a t ive a n a t om y of or ga n ic
r em a in s , p r om is es t o a ccom p lis h m a n y in t er es t in g d is cover ies in t h a t b r a n ch . H is
wor k on E n cr in it a l r em a in s , wh en s u b m it t ed t o t h e p u b lic, will for m a m od el of
s a ga ciou s , p a t ien t , a n d s u cces s fu l r es ea r ch .
a n ew Fos s il An im al
573
a s S ir E . Hom e h a s well ob s er ved : h e h a s a ls o fu lly d es cr ib ed t h e
p ecu lia r it y of t h eir s p in a l ca n a l, t h e a n n u la r p a r t n ot b ein g con s olid a t ed wit h t h e b od y, a s in qu a d r u p ed s , or con n ect ed b y a s u t u r e
a s in Cr ocod iles , b u t r em a in in g a lwa ys d is t in ct a n d u n it ed b y a
p ecu lia r join t . Th e figu r es will s u fficien t ly exp la in t h e for m of t h e
a n n u la r p a r t a n d t h e join t in qu es t ion ; t h is s t r u ct u r e is b elieved t o
b e p ecu lia r t o t h e Ich t h yos a u r u s .*
Th e a b s en ce of t r a n s ver s e p r oces s es , a n d t h e con s equ en t a r t icu la t ion of t h e r ib s t o t h e b od y of t h e ver t eb r æ b y d ou b le la t er a l
t u b er cles is a n ot h er im p or t a n t d is t in ct ive fea t u r e.
Th eir n a r r ow for m , or in ot h er wor d s , t h e s m a ll p r op or t ion wh ich
t h e len gt h of t h e s id e of t h eir b od y b ea r s t o t h e d ia m et er of it s
a r t icu la t in g s u r fa ce, is a n ot h er good a n d r ea d y cr it er ion . In t h e
Ich t h yos a u r u s , t h e len gt h of t h e s id e is les s t h a n h a lf t h e d ia m et er ;
in t h e ver t eb r a of a t r u e fos s il Cr ocod ile fou n d a t Gib r a lt a r in
Oxfor d s h ir e (t h e s a m e a p p a r en t ly wit h t h e 2 d fos s il s p ecies of M.
Cu vier ,) it s ligh t ly exceed s t h e d ia m et er ; a n d in t h e Ples ios a u r u s ,
wh ich h old s a n in t er m ed ia t e p la ce in t h is r es p ect , t h e r a t io of t h e
len gt h of t h e s id e t o t h e d ia m et er is n ever s o s m a ll a s on e h a lf, a n d
n ever s o gr ea t a s equ a lit y. Alt h ou gh t h e p r op or t ion s m a y s ligh t ly
va r y in d iffer en t p a r t s of t h e colu m n , t h e ch a n ge is n ot s u fficien t t o
a ffect t h is gen er a l exp r es s ion .
Th e t ot a l n u m b er of ver t eb r a : h a s n ot b een a s cer t a in ed , b u t it
*Th is m od e of a r t icu la t ion of t h e a n n u la r p a r t of t h e ver t eb r æ wit h t h eir b od ies , b y
a r egu la r join t , wa s n eces s a r y t o coop er a t e wit h t h e cu p p ed for m of t h e
in t er ver t eb r a l join t s , in givin g t h a t flexib ilit y t o t h e ver t eb r a l colu m n wh ich t h e
vib r a t or y m ot ion s n eces s a r y in t h e m od e of p r ogr es s ion , wh ich s eem s t o h a ve
b een com m on t o t h is a n im a l a n d fis h es , r eq u ir ed : for h a d t h es e p a r t s b een
con s olit a t ed a s in q u a d r u p ed s , t h eir a r t icu la t in g p r oces s es m u s t h a ve lock ed t h e
wh ole colu m n t oget h er s o a s t o r en d er s u ch a m ot ion of it s p a r t s im p os s ib le, b u t
b y m ea n s of t h is join t ever y p a r t yield s t o t h a t m ot ion .
574
Mr. De la BECHE a n d Mr. CONYBEARE on
ca n n ot b e les s t h a n b et ween eigh t y a n d n in et y, t h a t n u m b er b ein g
exh ib it ed on t h e s p ecim en figu r ed in t h e Ph il. Tr a n s . for 1 8 1 9 , a n d
a s s ever a l a r e t h er e d is p la ced , it is p r ob a b le t h a t s om e a r e m is s in g.
Th e ch a n ges in t h eir s t r u ct u r e cor r es p on d in g wit h a n d
in d ica t in g t h eir p la ces in t h e ver t eb r a l colu m n , a r e r ep r es en t ed in
t h e a ccom p a n yin g figu r es fr om a n ea r ly en t ir e colu m n in t h e
p os s es s ion of Colon el Bir ch .
Th e a t la s a n d a xis * h a ve n ot yet b een clea r ly a s cer t a in ed j b u t
t h er e s eem t o b e t r a ces of t h em in t h e fir s t b on es of t h e colu m n in
qu es t ion . At a n y r a t e, it is h igh ly im p r ob a b le t h a t m or e t h a n on e or
t wo of t h e a n t er ior ver t eb r a ca n b e m is s in g (if a n y a r e s o) in t h a t
s p ecim en . Th e n u m b er s a t t a ch ed t o t h e figu r es (fig. 1 2 , p la t e 4 1 ,)
in d ica t e t h eir p la ce in t h a t s er ies .
Th e s even t een fir s t h a ve b u t on e t u b er cle; t h ey a r e fa r t h er
d is t in gu is h ed b y t h e b r oa d er a n d p ecu lia r for m of t h e s ock et s in t o
wh ich t h e a n n u la r p a r t a r t icu la t es , wh ich in a ll t h e r em a in in g on es
is s t r a igh t a n d n a r r ow. Th e t h ir d ver t eb r a h a s b een s elect ed a s a
s p ecim en of t h es e, a n d t h e s even t een t h or la s t of t h em t o s h ew t h e
t r a n s it ion t o t h e n ext for m ; t h es e a r e evid en t ly cer vica l a n d
a n t er ior d or s a l.
Th e fa ls e r ib s a n d r ib s con n ect ed wit h t h es e ver t eb r æ m u s t h a ve
a r t icu la t ed b y a d ou b le h ea d , p a r t ly a ga in s t t h e t u b er cle, a n d
p a r t ly
*We h a ve s een on ly t h e in fer ior p iece or b od y (if it ca n b e s o ca lled ) of t h e a t la s ;
a n d t h e od on t oid p r oces s (wh ich a s in a ll t h e r ep t iles for m s a d is t in ct p iece) of t h e
a t la s ; t h ey ver y n ea r ly r es em b le t h os e of t h e t u r t le ; b u t we r efr a in fr om figu r in g
t h em t ill we s h a ll h a ve s een t h e p a r t s en t ir e. Th er e s eem t o b e s om e s p ecific
d iffer en ces in t h e for m of t h e t u b er cles in d iffer en t ver t eb r a l colu m n s of t h e
Ich t h yos a u r u s , p er h a p s t h ey m a y a ls o b e a ffect ed b y a ge ; t h ey a r e n ot h owever
s u ch a s t o a ffect t h e gen er a l a r r a n gem en t a n d p os it ion of t h em a s d es cr ib ed in t h e
t ext ; a ll t h e s m a ll s p ecim en s wh ich we h a ve s een , wh ich a r e gen er a lly t h e m os t
s h a r p ly m a r k ed , a gr ee wit h t h os e we h a ve figu r ed .
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a ga in s t t h e ca vit y left b y t h e p r olon ged lip of t h e s ock et in t o wh ich
t h e a n n u la r p a r t of t h e ver t eb r a is s et .
Th e t wen t y s u cceed in g ver t eb r a h a ve t wo a r t icu la t in g t u b er cles
t o s u p p or t t h e r ib s , a n d m u s t b e a s s ign ed t o t h e m id d le a n d
p os t er ior d or s a l a n d lu m b a r . Th e u p p er of t h es e t u b er cles is a t fir s t
p la ced clos e t o t h e lip of t h e a n n u la r s ock et , a n d t h en ce a s s u m es
gr a d u a lly a lower a n d lower p os it ion on t h e s id e, s o a s t o a p p r oa ch
m or e n ea r ly t o t h e in fer ior ; a t len gt h n ea r t h e for t iet h t h e t wo
t u b er cles r u n t oget h er a n d for m a s in gle r id ge.
Th e 1 8 t h , 2 5 t h , a n d 3 8 t h , h a ve b een s elect ed for r ep r es en t a t ion ,
a s exh ib it in g t h e m ea n for m of t h es e ver t eb r æ ; a n d t h eir p a s s a ge
in t o t h e a d join in g for m s on eit h er s id e.
Th e ch a n ges of p os it ion in t h es e p oin t s of a r t icu la t ion a t on ce
a ffect ed t h e s weep of t h e r ib s in for m in g t h e ca vit y of t h e t h or a x
a n d a b d om en , a n d t h eir m ot ion in op en in g it in r es p ir a t ion .
Th e ver t eb r a : h en ce t o t h e ext r em it y of t h e t a il h a ve n o m a t er ia l
ch a n ge, excep t in g t h a t t h e r id ge for m ed b y t h e u n ion of t h e t wo
t u b er cles , wh ich a t fir s t s t r et ch es a cr os s t h e b od y ob liqu ely, a t
len gt h b ecom es h or izon t a l. Th er e a r e a ls o t wo r id ges a cr os s t h e
b ot t om .
Th e r id ges on t h e s id e a p p ea r t o h a ve s u p p or t ed t h os e h or izon t a l
p r oces s es , wh ich will b e b et t er s een in t h e ca u d a l ver t eb r æ of t h e
p les ios a u r u s a s a n a logou s b on es a r e u s u a lly fou n d lyin g b y t h e
s id e of t h es e ver t eb r æ . Th e t wo in fer ior r id ges p r ob a b ly s u p p or t ed
t h e for k of t h e ch evr on -s h a p ed b on e wh ich occu r s in t h e t a il of a ll
t h e liza r d t r ib e, t h ou gh we h a ve n ot yet a ct u a lly s een it in t h is
a n im a l. Th e ch a r a ct er of t h es e ver t eb r a : is r ep r es en t ed b y t h e
for t y-s ixt h of t h os e fr om Col. Bir ch 's s p ecim en , a n d b y on e fr om
t h e ext r em it y of t h e t a il exh ib it in g t h e a n n u la r p a r t a t t a ch ed ,
b elon gin g t o Mr . J oh n s on .
VOL.
V. 4 D
576
Mr. De la BECHE a n d Mr. CONYBEARE on
Con cer n in g t h e r ib s , we h a ve n o n ew r em a r k t o offer , wit h t h e
excep t ion t h a t a ca r efu l exa m in a t ion of m a n y s p ecim en s h a s
con vin ced u s t h a t t h ey d id n ot for m a s in gle con t in u ou s a r c, a s t h e
a p p ea r a n ce of a s in gle s p ecim en in d u ced S ir E ver a r d Hom e t o
b elieve, b u t con s is t ed of s ep a r a t e r ib s on eit h er s id e wit h
in t er cos t a l b on es lyin g b et ween t h em a n d a t t a ch ed t o t h em b y
ca r t ila ges .
B on e s of th e S te rn u m a n d a n te rior e x tre m itie s *
Th es e h a ve b een m os t cor r ect ly a n d b ea u t ifu lly r ep r es en t ed in
Ph il. Tr a n s . for 1 8 1 7 a n d 1 8 2 0 , b u t it is wit h gr ea t d iffid en ce
t h a t we ven t u r e t o d iffer fr om S ir E ver a r d Hom e in t h e a n a logies
a n d n a m es a s cr ib ed t o t h e s ever a l p a r t s .
In t h e fir s t p la ce, we m a y ob s er ve a n a r ch ed b on e h a vin g a fla t
p r oces s p r oceed in g fr om t h e b ot t om of t h e a r ch . Th e wh ole for m
a n d a p p a r en t p os it ion in t h e s k elet on is ver y a n a logou s t o t h a t of
t h e b on e com m on ly ca lled t h e m er r y-t h ou gh t , a n d t ech n ica lly, t h e
fu r cu la , in b ir d s , † b u t it s in fer ior p r oces s is p a r a llel in s t ea d of
b ein g
* In t h e t ext t h e a p p ella t ion of cla vicles h a s b een a s s ign ed t o t h os e b on es in t h e
s k elet on s of t h e O r d er s , Rep t iles a n d Bir d s , wh ich a r e s o d en om in a t ed b y M.
Cu vier , in h is m em oir on fos s il cr ocod iles , b y Blu m en b a ch , a n d t h e m or e com m on
t r ea t is es on com p a r a t ive a n a t om y. It h a s b een s u gges t ed t o m e h owever t h a t m or e
r ecen t ob s er va t ion s s eem t o d em on s t r a t e t h e a n a logy of t h es e b on es wit h t h e
cor a coid p r oces s es of m a m m a lia r a t h er t h a n wit h cla vicles , a n d t h e fu r cu la for m s
in fa ct t h e t r u e r ep r es en t a t ive of t h e la t t er . If t h is view b e a d m it t ed , a s it h a s
s u cces s ively b een b y M. Cu vier , it will b e p r op er t o s u b s t it u t e in t h e t ext t h e t er m
cor a coid b on es for cla vicles , a n d cla vicu la r a r ch for fu r cu la . Th e a r gu m en t s on
wh ich t h e a b ove ch a n ges a r e fou n d ed p r oceed fr om t h e con s id er a t ion of t h e
m u s cles or igin a t in g in t h e b on es in q u es t ion .
† It m a y s eem ext r a or d in a r y t o s ea r ch for a n a n a logy in t h e s t r u ct u r e of a n im a ls
of s o wid ely d iffer en t a n or d er u s b ir d s , wh en t r ea t in g of a n y p a r t of t h e s k elet on
of a s p ecies in t er m ed ia t e b et ween cr ocod iles a n d fis h es ; yet t h e gen er a l
d is p os it ion of t h e a r ch ed b on e, t h e s ca p u la e, a n d cla vicles , is s o ver y s im ila r t h a t
it is im p os s ib le n ot t o r em a r k t h e r es em b la n ce ; a n d wh en it is con s id er ed t h a t t h e
em p loym en t a n d m ot ion of t h e p a d d le in s wim m in g h a s m a n y p oin t s of a gr eem en t
wit h t h a t of t h e win g in fligh t , " r em igio a la r u m ," we ca n n ot b e s u r p r is ed t h a t
n a t u r e, ever œ con om ica l in t h e a p p lica t ion of h er m ea n s , h a s given a s im ila r
s t r u ct u r e t o t h e p a r t s a d ja cen t t o t h e a n t er ior ext r em it ies in b ot h in s t a n ces .
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a t r igh t a n gles t o t h e lower p a r t of t h e ch es t ; in t h e
or n it h or yn ch u s , h owever , t h e
for m
of t h is
b on e
en t ir ely
a gr ees wit h t h a t of Ich t h yos a u r u s .
Th e t oa d h a s a s im ila r a p p a r a t u s , b u t con s is t in g of t h r ee d is t in ct
p ieces ; t h e in fer ior p r oces s a n d eit h er a r m of t h e a r ch for m in g a
s ep a r a t e h on e.
Th is b on e a lon e we con s id er a s b elon gin g p r op er ly t o t h e
s t er n u m ; we s h a ll t h er efor e ca ll it t h e s t er n a l a r ch .
Th e in n er s id e of t h e s ca p u læ is a t t a ch ed t o t h e a r m s of t h is
a r ch ; in t h is it a gr ees m os t n ea r ly wit h t h e or n it h or yn ch u s , in
wh ich h owever t h e ext r em it ies of t h e a r ch d o n ot p r oceed t h e wh ole
wa y b eh in d t h e s ca p u la :, b u t on ly a ffor d a s m a ll a r t icu la t in g fa ce.
Ii) t h e t oa d , a n d b ir d s , t h e ext r em it ies of t h e a r ch a r t icu la t e
b et ween t h e s ca p u la a n d cla vicle.
Th e fla t t en ed h a t ch et -s h a p ed b on e, t h e n a r r ow a n d exca va t ed
en d of wh ich u n it es wit h t h e s ca p u la t o for m t h e glen oid a l ca vit y,
a n d wh ich h a s b een con s id er ed a s a n a logou s t o t h e fla t b on es of
t h e or n it h or yn ch u s , a n d p ecu lia r t o t h es e a n im a ls , a p p ea r s ver y
ob viou s ly, on com p a r is on wit h t h e cor r es p on d in g p a r t s of t h e
cr ocod ile, t o b e a t r u e cla vicle, d iffer in g on ly in it s p r op or t ion s ,
b ein g s h or t er a n d t h er efor e wid er a t t h e fla t t en ed en d .
In t h e cr ocod ile, t h e t oa d , a n d b ir d s , t h e ext r em it ies of t h e
s ca p u la a n d cla vicle u n it e in t h e s a m e m a n n er t o for m t h e
glen oid a l s ock et ; a n d a ll a gr ee clos ely wit h t h e Ich t h yos a u r u s ,
excep t , a s h a s b een ob s er ved , in t h e s h or t er p r op or t ion a n d
b r oa d er en d of t h e cla vicle in t h e la t t er . Th e fla t t en ed b on es of t h e
or n it h or yn ch u s s h ou ld p r ob a b ly b e a ls o con s id er ed a s s u b s t it u t es
for cla vicles ; b u t t h ey d evia t e ver y wid ely in d eed fr om t h e gen er a l
for m , a lt h ou gh t h os e of t h e Ich t h yos a u r u s in s om e r es p ect s
p r es en t a n in t er m ed ia t e gr a d a t ion .
4 D2 .
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Mr. De la BECHE a n d Mr. CONYBEARE on
Th e wh ole of t h is s t r u ct u r e, t h e for m of t h e s t er n a l a r ch , a n d
t h e b r oa d s u r fa ces of t h e cla vicles , is s u ch , a s t o im p a r t gr ea t
s t r en gt h t o t h e ch es t , en a b lin g t h e a n im a l t o b r ea s t t h e m os t
d is t u r b ed wa t er s , a n d a ffor d in g a n ext en s ive s u r fa ce for t h e
a t t a ch m en t of p ower fu l m u s cles t o a s s is t in m ovin g t h e a n t er ior
ext r em it ies .
Th e glen oid a l ca vit y r eceives a b on e wh ich cor r es p on d s a t on ce
wit h h u m er u s , r a d iu s a n d u ln a , t h es e p a r t s b ein g s h or t en ed in
con s equ en ce of t h eir a d a p t a t ion t o s u p p or t a n ext r em it y cor r es p on d in g, in it s em p loym en t a t lea s t , r a t h er t o a fin t h a n a foot .
S om ewh a t s im ila r t a k es p la ce for t h e s a m e r ea s on s in t h e
h u m er u s , r a d iu s , a n d u ln a of t h e p or p ois e, wh ich a r e in lik e
m a n n er s h or t en ed a n d a n ch ylos ed ; h u t s t ill in t h a t a n im a l t r a ces
of t h eir d is t in ct for m m a y b e r ecogn is ed .
Th is h u m er o-r a d iu s s u p p or t s t h e b on es of t h e p a d d le, in wh ich
t h e fir s t fou r or five r ows m a y b e con s id er ed a s ca r p a l a n d
m et a ca r p a l, a n d t h e r em a in d er a s p h a la n gic, a lt h ou gh a ll t h e
b on es a r e n ea r ly s im ila r in for m , b ein g ir r egu la r fla t t en ed p olygon s .
Th ey a r e s o d is p os ed t h a t t h e fir s t r ow con s is t s of on ly t wo p ieces j
t h e s u cceed in g r ows , a s fa r a s t h e fift h , wh ich t h u s con t a in s s ix,
en cr ea s in g in a r it h m et ica l p r op or t ion ; in s om e s p ecim en s eigh t
m a y b e cou n t ed in t h e s u cceed in g r ows ; b u t t h e ext er ior p ieces a r e
ver y s m a ll a n d gen er a lly r em oved ; in len gt h t h er e a r e a b ou t t h ir t yfive of t h es e r ows , d ecr ea s in g t o a ver y s m a ll s ize n ea r t h e en d : t h e
b on es of t h e ext er ior s er ies h a ve a m or e r ou n d ed ou t lin e t h a n t h e
r es t ; t h e lon git u d in a l s er ies of t h es e p h a la n ges p r oceed in r igh t
lin es fr om t h eir b a s e in t h e ca r p u s ; t h e t wo fir s t b on es of t h e ca r p a l
p a r t m u ch r es em b le t h a t of t h e p or p ois e, a n d t h e t wo s u cceed in g
s er ies p r es en t a n a b s olu t e id en t it y of for m a n d a r r a n gem en t wit h
t h os e of t h e t u r t le, t o wh ich , a s we s h a ll h er ea ft er s ee, t h e p a d d le
of t h e n ewly d is cover ed p les ios a u r u s b ea r s a ls o t h r ou gh ou t a ver y
clos e a n a logy.
a n ew Fos s il An im al
579
B on e s of th e Pos te rior Ex tre m itie s .
Th os e of t h e p elvis h a ve n ot yet b een s een in a p er fect s t a t e; b u t
a s S ir E . Hom e h a s s t a t ed , t h ey clos ely r es em b le t h os e of t h e
Cr ocod ile. Th e fem or a l b on e a n d p os t er ior p a d d le a r e a lt oget h er
a n a logou s t o t h e h u m er u s a n d a n t er ior p a d d le ; b u t , con t r a r y t o
t h e p os t er ior ext r em it ies of qu a d r u p ed s in
gen er a l, ver y
con s id er a b ly s m a ller , n ea r ly in t h e p r op or t ion of on e t o t wo ; t h e
r ea s on s of t h is va r ia t ion a r e ob viou s ly t h e s a m e wh ich lea d t o a
s im ila r d im in u t ion of t h e a n a logou s p a r t s in s ea ls , a n d t h eir t ot a l
d is a p p ea r a n ce in cet a cea ; n a m ely t h e n eces s it y of p la cin g t h e
cen t r e of t h e or ga n s p r od u cin g a n d r egu la t in g m ot ion wh en a ct in g,
la t er a lly, b efor e t h e cen t r e of gr a vit y.*
Ge n e ra l R e m a rk s .
Fr om t h e d is loca t ed a n d im p er fect s t a t e of t h e s k elet on s of t h is
a n im a l, it is n ot ea s y t o a s cer t a in t h e r ela t ive p r op or t ion s of t h e
s ever a l p a r t s ; b u t fr om a ca r efu l exa m in a t ion of t h e m os t en t ir e, it
-wou ld a p p ea r t h a t t h e h ea d a n d ja ws occu p y a b ou t on e fou r t h of
t h e t ot a l len gt h of t h e a n im a l.
Th e s ize t o wh ich t h e a n im a ls of t h is gen u s s om et im es a t t a in ed
m a y b e in fer r ed fr om a h ea d in t h e p os s es s ion of Mr . J oh n s on of
Clift on , in wh ich t h e lon ges t a xis of t h e or b it is 1 4 ½ in ch es .
* Th is r em a r k a p p lies on ly t o a n im a ls m ovin g s wift ly t h r ou gh a s en s ib ly r es is t in g
m ed iu m ; for t h e s a m e r ea s on t h e win gs of b ir d s a r e p la ced in t h e for e p a r t of t h eir
b od y ; a n d t o t u r n t o wor k s of a r t , t h e cen t r e of t h e m ovin g for ces given t o s h ip s
b y t h eir s a ils is s im ila r ly p la ced ; wer e it ot h er wis e, a s ligh t d is t u r b in g for ce n ea r
t h e h ea d of t h e m ovin g b od y, wou ld in s t a n t ly s win g it r ou n d . Th e gr ea t or ga n of
m ot ion in fis h es , t h e t a il, is in d eed p os t er ior ly p la ced ; b u t t h is b y it s m od e of
a ct ion gen er a t es a vis a t er go, wh ich ca n on ly im p el t h e a n im a l s t r a igh t for wa r d s ;
a n d d oes n ot t h er efor e op er a t e u n d er t h e s a m e con d it ion s wit h or ga n s la t er a lly
a p p lied .
580
580
Mr. De la BECHE a n d Mr. CONYBEARE on
Com p a r in g t h e p r op or t ion s of t h is h ea d wit h t h a t of t h e en t ir e
s k elet on figu r ed in Ph il. Tr a n s . for 1 8 1 9 , it m u s t h a ve b elon ged t o
a n a n im a l exceed in g t wen t y-fou r feet in len gt h .
Th e geologica l s ea t of t h es e in t er es t in g r em a in s is p r in cip a lly in
t h e lia s , a n d in t h e cla y u n d er lyin g t h e Por t la n d oolit e a t
Kim m er id ge, a n d on S h ot over h ill, n ea r Oxfor d ; b u t t h ey h a ve
a ls o b een fou n d in s om e of t h e in t er m ed ia t e for m a t ion s , e. g. in t h e
ca lca r eou s gr it u n d er lyin g t h e Oxfor d oolit e a t Ma r ch a m n ea r
Oxfor d ; a n d a ga in in on e in s t a n ce in a for m a t ion s t ill m or e r ecen t
t h a n t h e Kim m er id ge cla y, n a m ely in a b ed of m a r ie a s s ocia t ed
wit h t h e gr een s a n d s er ies a t Ben s in gt on in Oxfor d s h ir e, p r ob a b ly
con t em p or a n eou s wit h t h a t of Folk s t on e in Ken t .
On t h e wh ole,
t h er efor e, it a p p ea r s t h a t t h e occu r r en ce of t h es e a n im a ls is a t
lea s t coext en s ive wit h t h e wh ole s er ies of for m a t ion s in t er ven in g
b et ween
th e
n ew r ed
s a n d s t on e a n d ch a lk : t h ey s eem
h owever t o b e m os t a b u n d a n t in t h e lia s . We h a ve s een
s p ecim en s
fr om
n u m er ou s
loca lit ies
s it u a t ed
on t h a t
for m a t ion in Dor s et s h ir e, S om er s et s h ir e, Glou ces t er s h ir e, a n d
Leices t er s h ir e.
It h a s b een ou r ob ject , in d r a win g u p t h e p r eced in g d et a ils on
t h e gen u s Ich t h yos a u r u s , t o es t a b lis h a fir m fou n d a t ion of
a n a t om ica l k n owled ge, wh ich m igh t b e a p p lied t o t h e illu s t r a t ion of
t h e n ewly d is cover ed gen u s p les ios a u r u s , t o wh ich it is ob viou s ly
in m a n y r es p ect s a llied . For s in ce, of t h e la t t er , com p a r a t ively few
s p ecim en s h a ve b een yet a ccu m u la t ed , a n d t h os e d eficien t in m a n y
im p or t a n t m em b er s , we a r e n ot a s yet in a s t a t e t o n eglect t h e a id s
t o b e d er ived fr om s u ch a n a logies .
To com m u n ica t e a n ot ice of t h e d is cover y of t h is n ew gen u s wa s
t h e p r in cip a l ob ject of t h e p r es en t p a p er ; yet , fr om t h e cir cu m s t a n ces a b ove m en t ion ed , ou r d er a ils con cer n in g it will
n eces s a r ily occu p y a fa r les s s p a ce t h a n t h os e wh ich s t r ict ly
s p ea k in g
wer e
a n ew Fos s il An im al
581
on ly p r elim in a r y. In t h is , a s wa s s t r ik in gly exem p lified in t h e
h is t or y of t h e d is cover ies con n ect ed wit h t h e for m er gen u s , we
d ou b t n ot b u t t h a t a n ea r ly a n d u n r es er ved com m u n ica t ion of
m a t er ia ls , wh ich fr om t h e cir cu m s t a n ces of t h e ca s e ca n n ot b u t b e
im p er fect , will s oon lea d t o t h e r em ova l of t h e p r es en t d eficien cies ,
a n d for t h e r ea s on s s t a t ed in t h e b egin n in g of t h is m em oir , we
t r u s t t h a t wh a t h a s a lr ea d y b een a s cer t a in ed , wh ich in d eed com p r is es t h e m os t m a t er ia l p oin t s con n ect ed wit h t h e t r u n k a n d a n t er ior ext r em it ies , will n ot b e fou n d en t ir ely d evoid of in t er es t .
PLE S IOS AURUS .
Ge n e ra l ch a ra cte r. A m a r in e a n im a l, in t er m ed ia t e in it s s t r u ct u r e
b et ween t h e Ich t h yos a u r u s a n d Cr ocod ile.
Te e th . Not h a vin g a s yet ob t a in ed a h ea d of t h is a n im a l, we
ca n n ot s p ea k wit h cer t a in t y on t h is s u b ject ; b u t a p ecu lia r t oot h ,
n ot b elon gin g t o a n y s p ecies of Ich t h yos a u r u s , yet evid en t ly of t h e
Cr ocod ilia n t yp e, occu r s in t h e lia s , a n d m a y wit h gr ea t p r ob a b ilit y
b e r efer r ed t o t h is a n im a l.
J a w a n d He a d b on e s . Not a s yet d is cover ed .*
Ve rte b ræ . Th es e a gr ee m or e n ea r ly wit h t h e Cr ocod ile t h a n wit h
t h e Ich t h yos a u r u s ; we s h a ll t h er efor e com p a r e t h em wit h t h e
for m er t yp e; s t a t in g fir s t t h eir p oin t s of a gr eem en t , a n d t h en of
d iffer en ce.
Th ey a gr ee wit h t h os e of t h e Cr ocod ile in h a vin g t h eir a n n u la r
p a r t a t t a ch ed t o t h e b od y b y s u t u r es ; t h os e in t h e you n ger s p ecim en s a llow t h e t wo p a r t s t o s ep a r a t e com p let ely, a n d for m a
clea n s ock et n ot u n lik e t h a t in t h e Ich t h yos a u r u s , b u t in t h e
old er s p ecim en s t h ey a r e com p let ely a n ch ylos ed : t h ey fa r t h er
a gr ee in h a vin g
* S in ce t h is p a p er wen t t o p r es s a few ver y im p er fect s p ecim en s h a ve occu r r ed ,
wh ich exh ib it ver y lit t le of a n illu s t r a t ive ch a r a ct er , excep t in g t h a t in t h is a n im a l
t h e t eet h wer e ca r r ied in d is t in ct a lveoli, a n d n ot in a con t in u ou s s u lcu s , a s in t h e
Ich t h yos a u r u s .
582
Mr. De la BECHE a n d Mr. CONYBEARE on
t r a n s ver s e p r oces s es t h r ou gh ou t t h e gr ea t er p a r t of t h e d or s a l ver t eb r æ , wh ich , t oget h er wit h t h e wh ole of t h e a n n u la r p a r t , ver y
n ea r ly r es em b le t h e cor r es p on d in g for m s in t h e t yp e a llu d ed t o.
Th e p r in cip a l d iffer en ces a r e.
1 s t In p la ce of b ein g con ca ve a t on e ext r em it y, a n d con vex a t t h e
ot h er en d , t h u s a r t icu la t in g b y a s p ecies of b a ll a n d s ock et -join t ,
t h ey a r e s ligh t ly con ca ve a t b ot h ext r em it ies of t h eir b od y, b u t
a ga in s ligh t ly s wellin g in a con t r a s t ed cu r ve n ea r t h e m id d le of t h e
cir cu la r a r ea . In t h es e fea t u r es h owever , t h ou gh t h ey d iffer fr om
r ecen t Cr ocod iles , t h ey a gr ee wit h on e s p ecies , a t lea s t , of t h os e
fou n d in a fos s il s t a t e in E n gla n d , Fr a n ce, a n d Ger m a n y; a n d a ll
t h e fos s il s p ecies a p p ea r t o h a ve t h is s t r u ct u r e in t h e p os t er ior p a r t
of t h e colu m n .—(S ee Cu vier O. F. T. 4 , a n d t h e d es cr ip t ion of
Cr ocod ilu s p r is cu s , in t h e Mu n ich Tr a n s a ct ion s .)
2 . Th ey d iffer fr om b ot h t h e fos s il a n d r ecen t s p ecies of Cr ocod ile
in m u ch n a r r ower p r op or t ion s ; t h ou gh fa r les s s o t h a n d o t h os e of
t h e Ich t h yos a u r u s . Th e p r op or t ion of t h e d ia m et er t o t h e len gt h of
t h e s id e b ein g n ea r ly a s 5 t o 4 in t h e cer vica ls , in t h e m id d le
d or s a ls a lit t le gr ea t er , a n d in t h e ca u d a ls n ea r ly d ou b le ; wh er ea s ,
t h e m ea n p r op or t ion in t h e fos s il Cr ocod iles we h a ve exa m in ed is
n ea r ly a n in ver s ion of t h e a b ove, t h e d ia m et er b ein g a lwa ys les s
t h a n t h e s id e.
3 . Th e n u m b er of cer vica l a n d d or s a l ver t eb r a in t h is a n im a l
a p p ea r s t o b e 4 6 ; a n u m b er a lm os t d ou b le t h a t of a n y r ecen t
S a u r ia n a n im a l, a n d gr ea t er t h a n even t h a t of t h e Ich t h yos a u r u s ,
wh ich d oes n ot s eem t o p os s es s a b ove 4 1 .
4 . Th ey fa r t h er d iffer fr om b ot h r ecen t a n d fos s il Cr ocod iles in
h a vin g t h e r ib s t h r ou gh t h e gr ea t er p a r t of t h e d or s a l s er ies a r t icu la t ed on ly t o t h e en d of t h e t r a n s ver s e p r oces s es ; a t lea s t , 2 8
a p p ea r t o b e t h u s cir cu m s t a n ced ; wh er ea s t h is t a k es p la ce in t h e
t h r ee
la s t
a n ew Fos s il An im al
583
of t h e Cr ocod ile on ly; in t h e ot h er S a u r ia n a n im a ls , h owever , a ll
t h e r ib s a r e t h u s b or n e.
Colon el Bir ch ’s s p ecim en exh ib it s a s er ies of 6 3 ver t eb r a :; b u t a s
t h ey wer e d u g loos ely ou t of t h e lia s m a r le in wh ich t h ey la y,
s ever a l a p p ea r t o b e m is s in g, a n d it com p r is es on ly t h e fir s t 1 2 of
t h e t a il. Mr . De la Bech e h a s a con t in u ou s ch a in of 1 8 m id d le
d or s a l; a n d , in t h e la t e Mr . Ca lcot t ’s collect ion , p r es er ved in t h e
cit y lib r a r y of Br is t ol, t h er e is a n ot h er con t in u ou s s er ies of 9 , t h e
8 t h of wh ich ca r r ies t h e la s t s h or t r ib ; t h is s p ecim en s eem s
for t u n a t ely t o h a ve s u cceed ed a lm os t im m ed ia t ely t o t h e for m er .
Fr om t h es e m a t er ia ls we a r e a b le t o give a t oler a b ly com p let e a ccou n t of t h is p a r t of t h e s k elet on .
Ou r figu r es a r e t a k en , u n les s wh er e it is ot h er wis e s t a t ed , fr om
Col. Bir ch ’s s p ecim en , wh ich b ein g a you n g a n im a l, h a s t h e a n n u la r p a r t s t ill s ep a r a t e, t h e s u t u r es n ot h a vin g yet a n ch ylos ed ,
a n d on t h is a ccou n t exh ib it s t h is p a r t of t h eir s t r u ct u r e, wh ich we
s h a ll d es ign a t e a s t h e a n n u la r s u t u r e, m or e d is t in ct ly j b u t in
ot h er p oin t s t h er e is n o va r ia t ion in old er s p ecim en s . Th e a t la s a n d
a xis we h a ve n ot s een .
Th e cer vica l a n d fir s t d or s a l ver t eb r æ a p p ea r t o h a ve p os s es s ed
s im ila r for m s . Th e ch a r a ct er of t h es e, wh ich ext en d t o t h e 1 2 t h in
Col. Bir ch '
s s er ies , is r ep r es en t ed in fig. 1 , 2 , 3 . p la t e 4 1 .
Th ey h a ve n o t r a n s ver s e p r oces s es ; t h e lin e of s u t u r e wit h t h e
a n n u la r p a r t is a n gu la r , a n d t h ey h a ve on eit h er s id e of t h e b od y a
d ou b le n ot ch , in t o wh ich a p p ea r s t o h a ve b een in s er t ed , b y a
d ou b le s t em , a t u b er cu la r p r oces s cor r es p on d in g t o t h e in fer ior
t u b er cle in t h e cer vica l a n d a n t er ior d or s a l ver t eb r æ of Cr ocod iles ,
a n d , lik e it , b ea r in g t h e fa ls e r ib s wh ich p r ot ect ed t h e n eck a n d t h e
fir s t t r u e r ib s .
Th e p os it ion of t h is d ou b le n ot ch is n ea r t h e b ot t om of t h e s id e
in t h e fir s t ver t eb r a , a n d gr a d u a lly a s cen d s t ill it a lm os t r is es t o,
and
VOL.
V.
4E
584
Mr. De la BECHE a n d Mr. CONYBEARE on
r u n s in t o t h e a n n u la r s u t u r e in t h e 1 2 t h . Fig. 1 r ep r es en t s t h e
ea r lies t for m ; fig. 2 . t h e s a m e, wit h t h e t u b er cu la r p r oces s
a t t a ch ed , b u t fr om a n ot h er s k elet on ; fig. 3 . t h e 1 2 t h ver t eb r a ; fig.
4. th e 13th .
In t h e cou r s e of t h e s u cceed in g fou r ver t eb r æ t h e u p p er of t h e
t wo n ot ch es r u n s in t o a n d ext en d s t h e m a r gin of t h e a n n u la r
s u t u r e; a n d in t h e n ext , (t h e 1 8 t h ) t h e lower n ot ch b ecom es a
d is t in ct t u b er cle ; t h u s t wo a r t icu la t in g s u r fa ces a r e a ffor d ed , on e
on t h e t u b er cle, a n d a s econ d on t h e ca vit y for m ed b y t h e
p r olon ga t ion of t h e lip of t h e s u t u r e, of wh ich t h e for m er m u s t
r eceive t h e h ea d , a n d la t t er t h e t u b er cle of t h e a n t er ior r ib s . It will
b e r em em b er ed t h a t a s t r u ct u r e exa ct ly s im ila r wa s p oin t ed ou t in
t h e cer vica l a n d a n t er ior d or s a l ver t eb r a : of t h e Ich t h yos a u r u s ; a n d
it cor r es p on d s a ls o in s om e d egr ee, a t lea s t , in t h e office of t h es e
p a r t s , wit h t h e fir s t d or s a l ver t eb r a of t h e Cr ocod ile, in wh ich t h e
t r a n s ver s e p r oces s is n ot yet fu lly d evelop ed , a n d r em a in s on ly a
t u b er cle. Fig. 5 A, a n d fig. 5 B, r ep r es en t t h e 1 8 t h ver t eb r a in t wo
p oin t s of view.
At len gt h t h e lower t u b er cle a ls o d is a p p ea r s , a n d is s wa llowed
u p in a s t ill lon ger p r olon ga t ion of t h e m a r gin of t h e a n n u la r
s u t u r e ; a t t h e s a m e t im e t h e s t em s b y wh ich t h e a n n u la r p a r t
wa s a t t a ch ed t o t h e b od y exp a n d t h eir b a s es la t er a lly, s o a s t o
for m in cip ien t t r a n s ver s e p r oces s es : t h es e a t fir s t p oin t
d own wa r d s , a n d a r e clos e t o t h e m id d le of t h e s id e, b u t a s t h ey
b ecom e lon ger t h ey r a p id ly a s cen d a n d p oin t u p wa r d s ; t h is
ch a r a ct er ext en d s t h r ou gh t h e m id d le of t h e d or s a l s er ies ;
t h en ce t h ey a ga in b egin t o in clin e d own wa r d s in t h e p os t er ior
d or s a ls , a n d in t h e la s t , wh ich b ea r s a ver y s h or t r ib , b ecom e
ver y m u ch r ed u ced . All t h e ver t eb r a fr om t h e fir s t d evelop em en t
of t h e t r a n s ver s e p r oces s (2 7 in n u m b er ) ca r r y t h e r ib s on a
s in gle
a r t icu la t in g
s u r fa ce
at
th e
en d
of
th at
p r o-
a n ew Fos s il An im al
585
ces s , lik e t h e t h r ee la s t d or s a ls in t h e Cr ocod ile a n d t h e wh ole
s er ies in m os t ot h er S a u r ia n s . Th e p oin t in g u p wa r d s of t h e
t r a n s ver s e p r oces s es in t h e m id d le of t h e s er ies s eem s in t en d ed t o
give a wid er s weep t o t h e r ib s fla n k in g t h e t h or a x a n d a b d om en .
All t h e ch a n ges la s t d es cr ib ed a r e r ep r es en t ed in t h e
a ccom p a n yin g figu r es , of wh ich fig. 6 r ep r es en t s t h e for m of t h e
ver t eb r a : fr om t h e 1 8 t h t o t h e 2 2 d , wh er e t h e m a r gin of t h e s u t u r e
for m s a r em a r k a b ly p r olon ged s in u s . Fig 7 A, a r id fig. 7 B,
r ep r es en t t h e in cip ien t a p p ea r a n ce of t h e t r a n s ver s e p r oces s a b ou t
t h e 2 2 d ver t eb r a . Th e b od y of t h is ver t eb r a is s h ewn fir s t
s ep a r a t ely, a n d t h en wit h t h e a n n u la r p a r t a t t a ch ed . Fig. 8 s h ews
t h r ee ver t eb r a : n ea r ly s u cceed in g t h is , b u t fr om a n ot h er m or e
p er fect a n d a ged s p ecim en . Fig. 9 A, a n d fig. 9 B, exh ib it t h e
m id d le d or s a l ver t eb r æ wit h a n d wit h ou t t h e a n n u la r p a r t , t o s h ew
t h e for m of t h e s u t u r e a n d it s d iffer en t con t ou r fr om t h a t in t h e
cer vica l a n d fir s t d or s a l; t h e p os t er ior d or s a ls d iffer on ly in h a vin g
t h e t r a n s ver s e p r oces s les s eleva t ed , a n d d id n ot t h er efor e r equ ir e
r ep r es en t a t ion .
Th e lu m b a r a n d ca u d a l ver t eb r a : a p p ea r t o d iffer in for m fr om
on e a n ot h er on ly in a les s in flect ion of t h e lower m a r gin , for t h e
p u r p os e s h or t ly t o b e m en t ion ed ; t h ey a r e h owever ver y d is t in ct
fr om a ll t h e ot h er s ; t h ey h a ve n o r egu la r t r a n s ver s e p r oces s es ,
b u t , in s t ea d of t h em , t wo s ep a r a t e b on es fla t t en ed a t t h e
ext r em it ies , a n d a r t icu la t ed in t o a s ock et n ea r t h e u p p er p a r t of
t h e s id es of t h e b od ies of t h e ver t eb r æ ; t h eir p os it ion is exa ct ly
h or izon t a l. We h a ve b efor e ob s er ved t h a t t h e Ich t h yos a u r u s
a p p ea r s t o h a ve h a d s im ila r b on es . Th e lower m a r gin of t h es e
ver t eb r a ; on t h e p os t er ior ext r em it y is in flect ed s o a s t o for m t wo
r egu la r in d en t a t ion s , exa ct ly a s in t h e Cr ocod ile, for t h e r ecep t ion
of t h e ch evr on -s h a p ed b on e b en ea t h t h e t a il. All t h es e
cir cu m s t a n ces a r e r ep r es en t ed in fig. 1 0 A, 1 0 B, 1 0 C, wh ich
exh ib it on e of t h e ea r ly ca u d a l ver -
4E2
586
Mr. De la BECHE a n d Mr. CONYBEARE on
t eb r æ in t h r ee p oin t s of view; a n d fig. 1 1 , wh ich r ep r es en t s on e
fa r t h er in t h e s er ies , t o s h ew t h e ch a n ge in t h e s ock et for t h e a r t icu la t ion of t h e la t er a l b on es , wh ich is m u ch n a r r ower , a n d is
h igh er p la ced .
We h a ve a s yet n o m ea n s of even s u r m is in g t h e n u m b er of
ca u d a l ver t eb r æ .
Th e m id d le d or s a ls a r e con s id er a b ly la r ger t h a n t h os e of t h e
ext r em it ies of t h e colu m n ; t h e m ea s u r es of t h r ee fr om d iffer en t
p a r t s of Col. Bir ch '
s wer e :
Dia m e te r of Articu la tin g S u rfa ce
Cer vica l
1 in ch
1¼
Mid d le Dor s a l
7/ 8
Ca u d a l
Le n gth of S id e .
6/
1
8
7/ 8
5/ 8
Th e la r ges t ver t eb r a of Ples ios a u r u s we h a ve yet s een wa s 2 ½
in ch es in d ia m et er .
On t h e wh ole, t h en , it a p p ea r s fr om t h es e r em a r k s , t h a t t h e ver t eb r a l colu m n of t h e Ples ios a u r u s r eced es fr om t h a t of t h e Ich t h yos a u r u s in a ll t h e p oin t s in wh ich t h e la t t er a p p r oa ch es t o t h e fis h ys t r u ct u r e ; t h a t t h e in t er ver t eb r a l s u b s t a n ce m u s t h a ve b een
d is p os ed m u ch a s in t h e Cet a cea , a n d t h a t on t h is a ccou n t , a s well
a s b eca u s e t h e a n n u la r p a r t s wer e fir m ly a t t a ch ed t o t h e b od ies ,
a n d t h er efor e, b y t h e lock in g in t o on e a n ot h er of t h eir a r t icu la t in g
p r oces s es , m u s t h a ve given a con s id er a b le d egr ee of s t a b ilit y t o t h e
colu m n , it m u s t h a ve p os s es s ed in a m u ch les s p er fect m a n n er t h e
flexib ilit y wh ich fa cilit a t es t h e p ecu lia r m ot ion of t h e Ich t h yos a u r u s
a n d of fis h es . Bu t it will b e p r es en t ly s een t h a t t h is wa s m u ch les s
n eces s a r y t o t h es e a n im a ls , in a s m u ch a s t h e s t r u ct u r e of t h eir
ext r em it ies r en d er ed t h em m u ch m or e p ower fu l in s t r u m en t s of
p r ogr es s ion .
To t h e d es cr ip t ion of t h es e ext r em it ies we n ext p r oceed ,
p r em is in g, t h a t we h a ve n ever s een t h e b on e wh ich we h a ve ca lled
in
th e
a n ew Fos s il An im al
587
Ich t h yos a u r u s , t h e fu r cu la or s t er n a l a r ch , wh ich we yet t h in k it
m os t p r ob a b le, fr om t h e for m of t h e s ca p u la , m u s t h a ve exis t ed in
t h is a n im a l a ls o.
A n te rior e x tre m ity .* It is p r op er t h a t we s h ou ld b egin b y s t a t in g,
t h a t a ll t h e b on es com p os in g t h is p a r t of t h e s k elet on wer e, in Col.
Bir ch ’s s p ecim en , loos e a n d d et a ch ed . Th e d et er m in a t ion of t h eir
exa ct s it u a t ion m a y t h er efor e b e con s id er ed a s in a cer t a in d egr ee
con ject u r a l; b u t we t r u s t t h a t t h e r ea s on s we s h a ll a lled ge will
p r ove s a t is fa ct or y, a n d lea ve lit t le if a n y d ou b t on t h e s u b ject .
Th e s ca p u la a n d h u m er u s r ep r es en t ed b y c a n d 6 , in t h e figu r es
of p la t e 4 2 , h a ve t h eir r ela t ion s p os it ively d et er m in ed b y a
s p ecim en in t h e Br is t ol lib r a r y collect ion , in wh ich t h ey occu r
t oget h er . Th is a ls o s h ews t h e for m of t h e la t t er b on e m or e
com p let ely, wh ich in Col. Bir ch ’s collect ion is m u ch com p r es s ed .
Th e s ca p u la , c, is s t ill s m a ller t h a n in t h e Cr ocod ile, b u t gen er a lly
r es em b les it in for m ; it s b a ck is s ligh t ly exca va t ed , wh ich gives it a
figu r e p r op er for a t t a ch m en t , a s in t h e Ich t h yos a u r u s , t o t h e
s t er n a l a r ch ; it s u p p er ext r em it y a ls o for m s a con ca ve t r ia n gu la r
a r t icu la t in g fa ce, wh ich p r ob a b ly r eceived a p r oces s fr om t h e
s t er n a l a r ch .
Th e h u m er u s , b , r equ ir es n o d es cr ip t ion ; it cou ld on ly b e con fou n d ed wit h t h e fem u r , a n d it s a s s ocia t ion wit h t h e s ca p u la r em oves t h is s u s p icion .
Th e fla t cla vicles , a , a , a r e s o exa ct ly s im ila r t o t h os e of t h e
Ich t h yos a u r u s , t h a t n o on e fa m ilia r wit h t h e la t t er b on es cou ld
h es it a t e in a s s ign in g t h eir p la ce. Th eir a r t icu la t in g s u r fa ces
m or eover (a lt h ou gh m u ch com p r es s ed in Col. Bir ch ’s s p ecim en ),
clea r ly coin cid e wit h t h os e of t h e s ca p u la , in for m in g t h e glen oid a l
ca vit y;
* If we follow t h e views s u gges t ed b y t h e la t e ob s er va t ion s on t h e m u s cles a t t a ch ed t o t h e
a n a logou s b on es in b ir d s a n d r ep t iles , we m u s t h er e, a s in t h e Ich t h yos a u r u s , con s id er wh a t
h a s b een t er m ed in t h e t ext t h e cla vicle a s r a t h er a n s wer in g t o t h e cor a coid p r oces s .
588
Mr. De la BECHE a n d Mr. CONYBEARE on
m or e es p ecia lly is t h is coin cid en ce vis ib le in t h e s ca p u la wh ich h a s
a n a r r owed a r t icu la t in g fa ce t owa r d s t h e cla vicle, a n d a b r oa d er t owa r d s t h e h u m er u s . Th e wh ole evid en ce t h en s t a n d s t h u s : s om e
b on e h a vin g a cer t a in a r t icu la t in g s u r fa ce wa s r equ is it e t o com p let e, t oget h er wit h t h e s ca p u la , t h e glen oid a l ca vit y; t h es e b on es
exa ct ly p os s es s t h e r equ is it e for m ; t h ey a gr ee exa ct ly wit h t h e
b on es h old in g t h e s a m e p la ce in t h e Ich t h yos a u r u s ; a n d t h er e is
n o ot h er p la ce in t h e s k elet on wh ich t h ey ca n b e s u p p os ed t o h a ve
occu p ied , excep t p er h a p s t h a t of os s a ilia , wit h wh ich h owever t h ey
will n ot b e fou n d , on ca r efu l exa m in a t ion , a t a ll t o a gr ee.
Th e b on es d , d , we h a ve a s s ign ed t o t h e office of r a d iu s a n d
u ln a , b eca u s e t h eir a r t icu la t in g s u r fa ces a t t h e on e en d a gr ee wit h
t h os e of t h e h u m er u s , a n d a t t h e ot h er wit h t h os e of t h e t h r ee
wh ich ob viou s ly for m t h e ca r p a l s er ies in t h e p a d d le, a n d b eca u s e
we ca n n ot d is cer n a n y ot h er equ a lly p r ob a b le p la ce in t h e
a r r a n gem en t of t h e s k elet on .
Of t h e p a d d le, t h e t h r ee fir s t or ca r p a l b on es m a r k ed c, e , e , a r e
well ch a r a ct er is ed ; of t h es e t h e cen t r a l h a s a for m n ot u n lik e t h a t
of t h e p h a la n ges of r ep t iles , b u t m or e fla t t en ed ; a n d wit h a r t icu la t in g ext r em it ies , for m in g a s m oot h a n d gen t le cu r ve ; t h e ext er ior
b on es h a ve a gen er a l t ext u r e lik e t h a t in t h e p a d d le b on es of t h e
Ich t h yos a u r u s , b u t h a ve a r en ifor m ou t lin e, a n d a r e m u ch
fla t t en ed .
Of t h e s u cceed in g b on es of t h e p a d d le, Col. Bir ch ’s s p ecim en
exh ib it s t wo fr a gm en t s ; on e (fig. 1 , p la t e 4 2 ) exh ib it in g t h r ee r ows
of p h a la n gic b on es , t o wh ich t h e d es cr ip t ion a lr ea d y given of t h e
cen t r a l ca r p a l b on e wou ld equ a lly a p p ly, a n d wh ich (excep t t h a t
t h ey a r e s h or t er ) clos ely r es em b le t h os e of t h e s ea t u r t le, m in gled
wit h
b on es
exa ct ly r es em b lin g t h e
r ou n d
b on es ,
wh ich
a n ew Fos s il An im al
589
for m t h e ext er n a l s er ies in t h e p a d d le of t h e Ich t h yos a u r u s . Th e
ot h er s p ecim en (fig. 2 ) exh ib it s t h es e p h a la n gic b on es in a lon git u d in a l s er ies , con t a in in g t r a ces of a t lea s t eleven r ows cou n t in g
len gt h wis e. Fr om t h es e s p ecim en s we m a y d r a w t h e followin g
con clu s ion s :
1 s t . Th a t t h e s er ies of s m a ll b on es for m in g t h e p a d d le wa s ver y
n u m er ou s , a p p r oa ch in g in t h is r es p ect t o t h e s t r u ct u r e of t h e
a n a logou s p a r t of t h e Ich t h yos a u r u s ; a n d s econ d ly, t h a t t h er e
wer e a s er ies of r ou n d b on es lik e t h os e wh ich for m t h e ext er n a l
b on es of t h e Ich t h yos a u r ia n p a d d le, a n d p r ob a b ly h old in g a lik e
p la ce; for s om e of t h os e in fig. 1 h a ve a la t er a l s it u a t ion (wh ich
wou ld b e r equ ir ed in t h is con for m a t ion ).
Th u s ,
t h er efor e, a gen er a l s im ila r it y of or ga n is a t ion
b et ween
t h is
im p or t a n t
m em b er
in t h e
Ples ios a u r u s
and
Ich t h yos a u r u s a p p ea r s t o b e es t a b lis h ed .
On t h e ot h er h a n d , a
com p a r is on wit h t h e p a d d les of t h e s ea t u r t le will exh ib it s u ch
fr es h a n a logies a s t o in d ica t e t h a t in r es p ect of t h e va r iou s for m s of
a n im a l ext r em it ies , t h e Ples ios a u r u s h old s a s it wer e a m id d le
p la ce b et ween it a n d t h e Ich t h yos a u r u s ; for we m a y r em a r k in t h e
fir s t ca r p a l s er ies of t h e t u r t le t h r ee b on es n ot u n lik e t h os e of t h e
Ples ios a u r u s ;
t h es e
are
s u cceed ed
b y t wo
r ows
exa ct ly
cor r es p on d in g, a s we h a ve b efor e ob s er ved , t o t h os e h old in g a
s im ila r p la ce in t h e Ich t h yos a u r u s . Th e cor r es p on d in g b on es in t h e
Ples ios a u r u s we h a ve n ot yet s een (u n les s in d eed t h os e of a
r ou n d ed for m n ot p la ced la t er a lly, a n d t h er efor e
for m in g t h e
ext er ior s er ies , b u t a t t h e en d of fig. I, m a y b e a ccou n t ed s u ch );
b u t t h e d ou b le a n a logies a b ove s t a t ed s ca r cely lea ve a d ou b t t h a t
t h ey lik ewis e h a d a s im ila r for m . Th e s u cceed in g a n d p h a la n gic
s er ies in t h e t u r t le exa ct ly a gr ee wit h t h os e of t h e Ples ios a u r u s in
for m , excep t in g t h a t t h ey
a r e in d ivid u a lly lon ger , a n d , a s in
qu a d r u p ed s ,
exh ib it
on ly
a
few
join t s ,
590
Mr. De la BECHE a n d Mr. CONYBEARE on
wh er ea s in t h e Ples ios a u r u s t h e com p a r a t ive s h or t n es s of t h e in d ivid u a l join t s is m u ch m or e t h a n com p en s a t ed b y t h eir
exceed in gly gr ea t er n u m b er , a n d a m u ch gr ea t er flexib ilit y is t h u s
im p a r t ed t o t h e wh ole p a d d le.
Her e t h en we m a y t r a ce a s er ies of lin k s b et ween t h e ext r em it ies
of la n d a n d s ea a n im a ls . Th e s ea t u r t le will for m t h e fir s t t er m of
t h es e, in wh ich t h e a r r a n gem en t a n d for m of t h e ca r p a l, m et a ca r p a l, a n d p h a la n gic b on es , will b e fou n d t o d iffer fr om ot h er
qu a d r u p ed s , a n d a p p r oa ch t o t h e Ples ios a u r u s in m a n y p oin t s ,
wh ile yet t h eir n u m b er a n d gen er a l a p p ea r a n ce m or e n ea r ly
r es em b le t h e u s u a l qu a d r u p ed a l t yp e. In t h e Ples ios a u r u s t h es e
p ecu lia r it ies h a ve a d d ed t o t h em t h a t of a m u ch gr ea t er n u m b er of
join t s , a n d a n ext er n a l s er ies of r ou n d ed b on es . In t h e
Ich t h yos a u r u s t h e u s u a l p h a la n gic for m is com p let ely a b a n d on ed ,
a n d a ll t h e b on es b ecom e ir r egu la r p olygon s or t r a p ezoid s , t h u s
a d m it t in g a s t ill gr ea t er n u m b er of s ep a r a t e join t s in t o t h e s a m e
s p a ce, a n d p r op or t ion a lly en cr ea s in g t h e flexib ilit y. In t h e fin s of
r egu la r fis h es , flexib ilit y is a ls o t h e ob ject a p p a r en t ly a im ed a t , a n d
p r od u ced b y t h e n u m b er of join t s a n d t h eir ca r t ila gin ou s
s u b s t a n ce, b u t t h eir for m m or e n ea r ly r es em b les t h a t of or d in a r y
p h a la n ges . We h a ve ven t u r ed t o a d d a figu r e of t h e p a d d le of t h e
Ples ios a u r u s , a s con ject u r a lly r es t or ed fr om t h e t wo fr a gm en t s ,
a n d t h e a n a logies a llu d ed t o, fig. 5 , p la t e 4 2 .
Th e gen er a l a r r a n gem en t of t h e wh ole ext r em it y is a ls o im p or t a n t , a s exh ib it in g a s im ila r gr a d a t ion of a r r a n gem en t ; for wit h
t h e fla t cla vicu la r b on es of t h e Ich t h yos a u r u s , a n d wit h t h e in t er m ed ia t e s p ecies of p a d d le a b ove d es cr ib ed , we fin d t h e d is t in ct
for m of h u m er u s , r a d iu s , a n d u ln a , b elon gin g t o qu a d r u p ed s
gen er a lly.
Of t h e p os t er ior ext r em it ies , we h a ve s een s om e im p er fect b on es
of t h e p elvis a n d fem or a ; b u t we p os t p on e a n y a t t em p t t o d es cr ib e
t h is p a r t of t h e a n im a l, t ill fu t u r e op p or t u n it ies s h a ll h a ve p r ovid ed
u s wit h m or e illu s t r a t ive s p ecim en s .
a n ew Fos s il An im al
591
Ge ologica l S e a t of th e R e m a in s of th e Ple s ios a u ru s , a n d oth e r
S a u ria n R e m a in s fou n d in th is Is la n d .
We a r e a s yet a cqu a in t ed wit h n o in s t a n ce of t h e occu r r en ce of
t h e r em a in s of t h e Ples ios a u r u s in a n y ot h er for m a t ion t h a n t h e
lia s , wh er e t h ey h a ve b een fou n d in Dor s et s h ir e, S om er s et s h ir e,
Glou ces t er s h ir e, a n d Leices t er s h ir e, in t h e s a m e loca lit ies wit h
t h os e of t h e Ich t h yos a u r u s .
In con clu s ion , we s h a ll s u b m it , in or d er t o a t t r a ct m or e gen er a l
n ot ice t o t h e en qu ir y, a s h or t lis t of t h e ot h er va r iet ies of S a u r ia n
a n im a ls , wh ich , a s fa r a s ou r k n owled ge ext en d s , h a ve b een fou n d
in a fos s il s t a t e in t h is is la n d .
We h a ve n ever s een a n y gen u in e r em a in s of t h e cr ocod ile in t h e
lia s of t h e s ou t h er n cou n t ies ; t h os e wh ich h a ve b een u s u a lly con s id er ed a s s u ch r ea lly b elon gin g t o t h e Ples ios a u r u s . Th is a ls o is
t h e ca s e wit h t h e s p ecim en d is cover ed b y S t u k ely a t Newa r k in
Not t in gh a m s h ir e, a n d d es cr ib ed in t h e Ph ilos op h ica l Tr a n s a ct ion s ,
wh ich , fr om t h e im p er fect ion of t h e p la t e t h er e given , M. Cu vier
wa s led t o con s id er a s a cr ocod ile. We h a ve n ot h owever , a s yet ,
h a d a n op p or t u n it y of exa m in in g t h e b on es fr om Wh it b y.
Rem a in s of a n u n d ou b t ed s p ecies of cr ocod ile, s om ewh a t r es em b lin g t h e Ga via l, h a ve b een fou n d in t h e u p p er b ed s of t h e
gr ea t oolit e, or in t h e Cor n b r a s h , for t h e d is t in ct ion b et ween t h es e
b ed s ca n n ot in t h a t p a r t of t h e cou n t r y b e a s cer t a in ed , a t
Gib r a lt a r , eigh t m iles n or t h of Oxfor d , on t h e r iver Ch er well ; t h e
ver t eb r a of t h is va r iet y a gr ee wit h t h e s econ d s p ecies fr om
Hon fleu r , d es cr ib ed b y M. Cu vier , in h a vin g b ot h fa ces of t h e
ver t eb r a : s ligh t ly con ca ve lik e t h e Ples ios a u r u s ; b u t t h eir
p r op or t ion s , a r t icu la t in g s u r fa ces for t h e r ib s , &c. a gr ee clos ely
wit h t h e cr ocod ile, a s d oes t h e h ea d , wh ich h a s a ls o b een fou n d .
VOL. V.
4 F
592
Mr. De la BECHE a n d Mr. CONYBEARE on
An ot h er h ea d , b u t a p p a r en t ly of a d iffer en t s p ecies , h a s b een
fou n d in t h e Por t la n d lim es t on e in t h e Is le of Pu r b eck , a n d is n ow
in t h e p os s es s ion of Mr . J oh n s on of Clift on .
An im m en s e S a u r ia n a n im a l, a p p r oa ch in g t o t h e ch a r a ct er s of
t h e Mon it or , b u t wh ich , fr om t h e p r op or t ion s of m a n y of t h e
s p ecim en s , ca n n ot h a ve b een les s t h a n for t y feet lon g, occu r s in
t h e gr ea t oolit e a t S t on es field , n ea r Oxfor d . Pr ofes s or s Kid d a n d
Bu ck la n d h a ve b een lon g en ga ged in t h e s t u d y of t h es e in t er es t in g
r em a in s , a n d it is h op ed m a y s oon com m u n ica t e t h e r es u lt of t h eir
ob s er va t ion s t o t h e p u b lic. Ver t eb r æ a n d p h a la n ges of a n ot h er
a n im a l, a p p a r en t ly a llied t o t h e E n a lio-S a u r i d es cr ib ed in t h is
p a p er , b u t clea r ly of a d is t in ct gen u s , occu r in t h e Kim m er id ge cla y
in t h e p it s a t t h e foot of S h ot over h ill n ea r Oxfor d .*
* In Wh it eh u r s t ’s Th eor y of t h e E a r t h , p . J 8 4 , it is m en t ion ed t h a t t h e im p r es s ion
of a cr ocod ile wa s fou n d a t As h for d , in t h e fir s t b ed of t h e m ou n t a in lim es t on e of
D er b ys h ir e, b y Mr . H en r y Wa t s on of Ba k ewell. As t h is is ver y im p or t a n t in
in d ica t in g t h e t r a ces of t h es e a n im a ls in a n old er for m a t ion t h a n t h os e a b ove
m en t ion ed , a n d on e in d eed in wh ich t h e ver y exis t en ce of Ver t eb r a l a n im a ls h a s
b een d en ied , (a lt h ou gh cer t a in ly on ly in con s eq u en ce of a ver y p a r t ia l
a cq u a in t a n ce wit h t h e or ga n ic r em a in s it a ffor d s , a m on g wh ich t h e p a la t a l t r it or es
of fis h es , t h e in cis or es of t h e s h a r k , a n d t h e r a d ii of Ba lis t æ a r e n ot ver y
u n com m on ), it is ver y d es ir a b le t o ob t a in fu r t h er in for m a t ion con cer n in g t h is
s p ecim en , if it b e yet in exis t en ce, a n d p a r t icu la r ly (s in ce t h e t er m Cr ocod ile h a s
oft en b een ver y va gu ely a p p lied ) a p r ecis e a ccou n t of it s s p ecific ch a r a ct er s . Wit h
t h e view of lea d in g t o s u ch a r es u lt , we h a ve a d d ed t h is n ot e.
Th e followin g a r t icle, ext r a ct ed fr om t h e p r os p ect u s of Mr . Ma n t ells 'exp ect ed
wor k on t h e G eology a n d F os s ils of S u s s ex, con t a in s a n ot h er in t er es t in g n ot ice
con n ect ed wit h t h is s u b ject . " 4 1 Lower ja w of a n a n im a l of t h e Liza r d t r ib e, in
ch a lk , con - t a in in g t welve t eet h . Two Ver t eb r æ in ch a lk , of t h e celeb r a t ed fos s il
a n im a l of Mæ s t r ich t ." I a m a ls o in d eb t ed t o h im for t h e followin g com m u n ica t ion
on t h is s u b ject .
In t h e lim es t on e of t h e O a k Tr ee Cla y, or Wea ld Cla y of S u s s ex, n u m er ou s
r em a in s occu r of a n a n im a l of t h e Liza r d t r ib e. F r a gm en t s of t h e r ib s , cla vicle,
r a d iu s , p u b is iliu m , fem u r , t ib ia , m et a t a r s a l h on es , ver t eb r æ , a n d t eet h , h a ve
b een d is cover ed ; a n d a lt h ou gh t h e s p ecim en s a r e, for t h e m os t p a r t , exceed in gly
m u t ila t ed , yet t h e s t r u ct u r e o t h e or igin a l a n im a l is ver y clea r ly in d ica t ed . F r om
a n a t t en t ive exa m in a t ion of t h es e r em a in s , t h er e ca n b e n o h es it a t ion in
con s id er in g t h em a s b elon gin g t o t h e s a m e u n -
a n ew Fos s il An im al
593
P. S . Wh ile t h is p a p er wa s p a s s in g t h r ou gh t h e p r es s , t h e a u t h or
h a s r eceived a com m u n ica t ion fr om a fr ien d r es id en t in Pa r is , in
wh ich it is s t a t ed , t h a t t h e d is cover y of t h e com p os it ion of t h e
lower ja w of t h e Ich t h yos a u r u s in a m a n n er a n a logou s t o t h a t of
t h e a n im a ls of t h e S a u r ia n fa m ily, h a d b een a n t icip a t ed b y Mr .
Cu vier , a n d com m u n ica t ed in t h e a u t u m n of 1 8 2 0 t o Mes s r s .
Lea ch a n d Clift , a lt h ou gh it a p p ea r s t h a t t h e gen er a l fa ct on ly h a d
b een ob s er ved , a n d t h a t t h e d et a ils of t h e s t r u ct u r e of t h is p a r t h a d
n ot b een fu lly exa m in ed .
Th e a u t h or is h a p p y t o h a ve a n op p or t u n it y of m a k in g t h is
a ck n owled gm en t ; h e wa s en t ir ely ign or a n t of t h is a n t icip a t ion
u n t il h is own ob s er va t ion s h a d b een com m it t ed t o t h e p r es s .
k n own s p ecies of Cr ocod ile, a s t h e os s eou s r em a in s d is cover ed a t H on fleu r a n d
H a vr e, wit h wh ich t h ey a ls o a ccor d in t h eir m od e of p et r ifa ct ion , : a n d in t h e
n a t u r e of t h e s t r a t u m in wh ich t h ey a r e en t om b ed . Vid e Cu vier , An im a u x F os s iles ,
Tom . IV. p . 1 7 , 1 8 .
Crocod ile s .
Ta b . XXXIII.—All t h e s p ecim en s d elin ea t ed in t h is p la t e a r e fr om t h e u p p er ch a lk .
F ig. 1 . Con ica l s t r ia t ed t oot h . Mr . Kon ig s u p p os es it t o b elon g -t o t h e
Ich t h yos a u r u s , ot h er s t h a t it r es em b les t h e in cis or t eet h of Aa a r r h icu s
lu p u s .
F ig. 1 0 . Ver t eb r æ of t h e Ich t h yos a u r u s ?
F ig. 1 3 . Cer t a in ly t h e ver t eb r a : of a s p ecies of Cr ocod ile.
Ta b . XXXIX.—D or s a l fin of a fis h of t h e gen u s Ba lis t es ? in ch a lk .
Ta b . XLI.—F ig. 1 . " Ver y lik e in m in ia t u r e t h e la r ge a m p h ib iou s a n im a l of
Ma a s t r ich t
in ou r Mu s eu m :
I s h ou ld n ot h es it a t e t o con s id er it a s a s p ecies of
la cer t a ."—Mr . Kön ig.
F ig. 2 . F r on t view of t h e t wo a n t er ior t eet h .
I d o n ot t h in k t h a t t h is
s p ecim en m a y n ot h a ve b een t h e ja w of a fis h .
F ig. 3 . Two ver t eb r a ; of t h e celeb r a t ed a n im a l of S t . Pet er ’s m ou n t a in : t h es e
cer t a in ly r es em b le t h e s p ecim en s in t h e Br it is h Mu s eu m , a n d a ls o t h os e
figu r ed b y F a u ja s S t . F on d .
Ta b . XLII.— Th e wh ole of t h e s p ecim en s figu r ed in
t h is p la t e wer e d is cover ed in on e
b lock of ch a lk .
Th e r em a in s of a n u n k n own fis h ? s om e s a y La cer t a ?
4 F2
594
Mr. De la BECHE a n d Mr. CONYBEARE on
On t h e s a m e a u t h or it y it is s u gges t ed t h a t t h e h u m er o-s t er n a l
p a r t of t h e Ich t h yos a u r u s a n d Ples ios a u r u s , viz. t h e fu r cu la ,
cor a coid p r oces s es , &c. b ea r a gr ea t er a n a logy t o t h e Mon it or
Igu a n a , a n d ot h er s of t h e La cer t a s t h a n t o t h e Cr ocod ile. Th e
p r es en t wr it er h owever is s t ill in clin ed , fr om t h e com p a r is on of t h e
os t eology of t h e h ea d , t o a p p r oxim a t e t h e Ich t h yos a u r u s r a t h er t o
t h e la t t er t h a n t h e for m er .
--------------------------------------------------S in ce t h e com p let ion of t h e p r es s , I h a ve r eceived fr om Mr . De la
Bech e t h e followin g p a r t icu la r s of a s p ecim en of Ich t h yos a u r u s
la t ely d is cover ed a t Lym e, wh ich I a m a n xiou s t o s u b join , a s t h ey
s h ew t h e t ot a l n u m b er of ver t eb r a : a n d r ib s in t h is a n im a l.
Th e s p ecim en (I. com m u n is ) la t ely fou n d , is ver y in t er es t in g; it
con s is t s of t h e h ea d , wit h a ll, or n ea r ly a ll, t h e ver t eb r a in p la ce ,
wit h t h e excep t ion of t wo. Th e t ot a l n u m b er of ver t eb r a ; a m ou n t s
t o 1 0 4 , n ot in clu d in g t h e a t la s a n d a xis , wh ich a r e a ls o in p la ce ;
d ia m et er of t h e la r ges t d or s a l ver t eb r a : ly in ch . Th is s p ecim en
con t a in s 3 1 r ib s on ea ch s id e, wh ich I t a k e t o b e t h e r ea l n u m b er
of r ib s t h a t t h e Ich t h yos a u r u s p os s es s ed , a s n on e a p p ea r t o b e
wa n t in g; len gt h of t h e la r ges t r ib ll½ in ch es ; t h e lower ja w 1 foot
6 ½ in ch es lon g, is in t oler a b le con d it ion ; t h e ot h er b on es of t h e
h ea d , wit h t h e excep t ion of t h e m a xilla r y a n d in t er m a xilla r y b on es ,
a r e m u ch cr u s h ed . Th e ch evr on b on es com e in b ea u t ifu lly a ft er t h e
r ib s cea s e. Th e ver t eb r a l colu m n in cr ea s es (a s in t h e Pr ot eos a u r u s )
fr om t h e a t la s a n d a xis t o t h e m id d le d or s a l, a n d t h en d ecr ea s es t o
t h e ext r em it y of t h e t a il. Th er e a r e t r a ces of t h e p elvis in t h is
s p ecim en ; it m u s t h a ve b een ver y s im p le, a s a ft er a ca r efu l
exa m in a t ion I cou ld n ot d et ect a n y d iffer en ce in t h e ver t eb r æ a b ou t
th e
p la ce
wh er e
it
ou gh t
to
be
a t t a ch ed .