We recognize five classes within Phylum Echinodermata for the purpose of this course. All organisms within this phylum possess a unique water vascular system composed of coelomic canals.

Figures to know & Cladogram

Class Asteroidea Images
Starfish-ambulacral-groov
Starfish-or-sea-star
Starfish-oral-aboral-A
Starfish-oral-&-aboral-B

Class Ophiuroidea Images
Basket-star

Class Echinoidea Images
Sand-dollar
Sand-dollars
Sea-urchin-cut-to-show-Aris
Sea-urchin-variety
Typical-sea-urchin

Class Crinoidea images
Crinoidea
Shaken specimen of crinoid in a jar

Class Holothuroidea Images
Sea-cucumber
Sea-cucumber-dissected
Sea-cucumber-eviscerated