1
2
Phylum Echinodermata: “spiny skin”
- sea stars, brittle stars, sea cucumbers, sea lilies, urchins•  General Features
–  Exclusively marine
–  Benthic herbivores, detritovores,
carnivores;
–  All habitats/depths
–  Bilateral larvae, radial adult
–  Endoskeleton
–  Non-centralized nervous system
–  Water-vascular system
–  Non-segmented
–  Well developed digestive system
–  Cutaneous respiration
–  Regenerative Capacity
3
5 Echinoderm Classes
4
!
Figure 33.38 Anatomy of a sea star
Cl. Ophiuroidea
Cl. Crinoidea
5
Cl. Asteroidea
Cl. Echinoidea
Cl. Holothuroidea
6
1
7
Water Vascular System
8
Tube feet
movies
9
Echinoidea
11
10
Aristotle’s lantern
12
Sand dollar
Ophiuroidea
2
14
Crinoids
16
15
Holothuroidea
17
18
Larval Stage
3