Figures
Figure 1. Pseudopenis and penis of Thais chocolata. a – c. Macroscopic view of the pseudopenis.
Scale bar = 1 cm. a. Location of the pseudopenis, behind the right tentacle. In the anterior part of the
pseudopenis is located a filiform extension. b. Ocurrence of two pseudopenis. c. Dense structure
(arrowhead) and pseudopenile tissue fusion. dg: digestive gland; f: filiform; me: mantle edge; o:
ovary; pp: pseudopenis; r: rectum; rt: right tentacle; tf: tissue fusion.
Figure 2. Trasnverse histological sections of the pseudopenis duct and penis duct of Thais chocolata.
a – b. Scale bar = 50 µm. a. Narrow lumen (arrow) of the pseudopenis duct and surrounded by a
thick circular musculature in female. b. Lumen (arrow) of the penis duct surrounded by a circular
muscle in male. m: muscle.
Pseudopenis/Penis Length (mm)
25.0
Females:
2
20.0
n=90, r = 0.5, p < 0.05
15.0
Males:
Females
Males
2
n=90, r = 0.7, p < 0.05
10.0
5.0
0.0
0.0
20.0
40.0
60.0
80.0
100.0
120.0
Shell Length (mm)
Figure 3. Lineal correlation of the shell length (mm) and pseudopenis/penis length (mm) of females
and males of Thais chocolata from Caldera Bay.
Figure 4. Vulva of Thais chocolata female. a. Macroscopic view of vulva occluded by the vas
deferens. Scale bar = 1 cm. b. Transverse histological section of prostatic glands (arrows) on the
periphery of the vulva musculature. Scale bar = 200 µm. cg: capsule gland; v: vulva; vd: vas
deferens; vm: vulva musculature.
Figure 5. Capsule gland of Thais chocolata female. a. External view of the gland. Note the nodular
structures. b. Gland with aborted ovicapsule mass (arrow). Inset: external view of aborted ovicapsule
mass. a – b scale bar = 1 cm. c – f. Transverse histological sections of capsule gland. c. Modified
cylindrical epithelium of the gonoduct. Scale bar = 80 µm. d. Glandular tissue with acellular areas
and low dye affinity (arrows). Scale bar = 20 µm. e. Detail of pyknotic nuclei (arrows). Scale bar = 5
µm. f. Prostatic glands on the periphery of capsule gland. Scale bar = 70 µm. cg: capsule gland; cyl:
cylindrical; cub: cubic; n: nodular; r: rectum; pg: prostatic gland.
Figure 6. Transverse histological section of ingestive gland of Thais chocolata female. Saccules of
ingestive gland. It highlighted on the periphery of the gland, the occurrence of acini of prostatic gland
(arrows). Scale bar = 200 µm. sc: saccules.
Figure 7. Transverse histological sections of albumen gland of Thais chocolata female. a. Modified
cylindrical epithelium of gonoduct. Scale bar = 70 µm. b. Gonoduct epithelium with lack of basal
lamina. Scale bar = 20 µm. c. Diffuse demarcation (arrows) between albumen and capsule glands. d.
Acini of prostatic gland on the periphery of albumen gland. c – d scale bar = 200 µm. ag: albumen
gland; cg: capsule gland; cyl: cylindrical; ps: pseudostratified.