Phylum Echinodermata Classes
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Class Asteroidea
Class Asteroidea
1. Have 5 arms usually
2. Mouth located in center of oral surface
pointing downward
3. Has a Water Vascular System with tube feet
4. Has Mouth and Stomach
5. Has short intestine – extends from stomach to
anus.
6. Endoskelton made up of calcareous plates that
penetrate the dermis as spines
7. Between the spines and plates are projections
called papulae, which function in gas
exchange and excretion
8. Other projections on the body wall include tiny
jaw-like appendages called pedicellaria
9. Has Photoreceptors
10. Examples: Starfish, Brittle stars
1. Have 5 arms usually
2. Mouth located in center of oral surface
pointing downward
3. Has a Water Vascular System with tube feet
4. Has Mouth and Stomach
5. Has short intestine – extends from stomach to
anus.
6. Endoskelton made up of calcareous plates that
penetrate the dermis as spines
7. Between the spines and plates are projections
called papulae, which function in gas
exchange and excretion
8. Other projections on the body wall include
tiny jaw-like appendages called Pedicellaria
9. Has Photoreceptors
10. Examples: Starfish, Brittle stars
Class Ophiuroidea
Class Ophiuroidea
1. Characteristics similar to class Asteroidea
2. Main difference between starfish and brittle
stars is brittle stars have much thinner arms.
3. Examples: Brittle stars
Class Echinoidea
1. No arms
2. Body is enclosed in a shell or test
3. Body surface is usually covered with
moveable spines
4. Spherical body
5. Ambulacral plates bearing tube feet that
radiate out toward the aboral surface
6. Use podia and spines during locomotion
7. The spines are moveable and articulate
with the with the calcareous ossicles
8. Examples: Sea Urchins, Sand Dollars
9. Feeding – Scrap algae off of rocks then
using a chewing apparatus called
Aristotle's Lantern
1. Characteristics similar to class Asteroidea
2. Main difference between starfish and brittle
stars is brittle stars have much thinner arms.
3. Examples: Brittle stars
Class Echinoidea
1. No arms
2. Body is enclosed in a shell or test
3. Body surface is usually covered with
moveable spines
4. Spherical body
5. Ambulacral plates bearing tube feet that
radiate out toward the aboral surface
6. Use podia and spines during locomotion
7. The spines are moveable and articulate
with the with the calcareous ossicles
8. Examples: Sea Urchins, Sand Dollars
9. Feeding – Scrap algae off of rocks then
using a chewing apparatus called
Aristotle's Lantern
Class Holothuroidea
1. No arms
2. Endoskeleton is reduced to a few Ossicles
on the surface
3. Fairly soft-bodied
4. Locomotion – using false feet and by
muscular contractions
5. Examples: Sea Cucumber
6. Oral end of the body has a group of
tentacles surrounding the mouth; used
in feeding
7. Have a muscular cloaca that is partly used
in gas exchange
8. Gas exchange structures are branching
structures called respiratory trees
Class Holothuroidea
1. No arms
2. Endoskeleton is reduced to a few Ossicles
on the surface
3. Fairly soft-bodied
4. Locomotion – using false feet and by
muscular contractions
5. Examples: Sea Cucumber
6. Oral end of the body has a group of
tentacles surrounding the mouth; used
in feeding
7. Have a muscular cloaca that is partly used
in gas exchange
8. Gas exchange structures are branching
structures called respiratory trees
Class Crinoidea
1. Most primitive of echinoderms
2. Oral surface is upward
3. Has a stalk
4. Body portion attached to the stalk is the
crown;
5. Has branches called pinnules
6. Ciliated around the mouth
Class Crinoidea
1. Most primitive of echinoderms
2. Oral surface is upward
3. Has a stalk
4. Body portion attached to the stalk is the
crown;
5. Has branches called pinnules
6. Ciliated around the mouth