Diagram of Phyla Echinodermata 

Class Asteroidea

(sea stars) 

star shaped body with multiple arms; mouth directed to substrate

radial symmetry

Asteroidea 

Asteroidea

Asteroidea 

Asteroidea 

Asterias 

Class Crinoidea

(A feather star)

long, flexible arms

arms used in suspension feeding

arms encircle the mouth, directed upward 

Crinoidea 

Crinoidea 

Class Echinoidea

(a sea urchin or sand dollar) 

have no arms

five rows of tube feet that function in slow movement

sand dollars- flattened and disc shaped

mouth ringed by complex, jaw like structure 

Echinoidea 

Echinoidea 

Echinoidea 

Echinoidea 

Echinoidea 

Echinoidea 

Sand Dollar 

Class Holothuroidea

( sea cucumbers) 

lack spines

reduced endoskeleton

elongated in their oral-aboral axis

5 rows of tubed feet

some tube feet are modified feeding tentacles 

Holothuroidea 

Sea Cucumber 

Class Ophiuroidea

(brittle stars) 

dinstinct central disk

long flexible arms

tube feet lack suckers

most are suspension feeders 

Ophiuroida 

Brittle Star 

phylum echinodermata share common characteristics with chordata (animals w/ backbones)

they are both deuterostomes. list three characteristics of deuterostomes

radial symmetry

glastopore at the mouth

coleum formation