Reference

(n.d.). Sea cucumbers. Retrieved from http://www.enchantedlearning.com/subjects/invertebrates/echinoderm/seacucumber/printout.shtml

(n.d.). Class holothuroidea. Retrieved from http://animaldiversity.ummz.umich.edu/site/accounts/information/Holothuroidea.html

Habitat

Holothuroidea are found in every type of environment in the ocean floor from tropical water to deep cold water.

Taxonomy

Kingdom: Animalia
Phylum: Echinodermata
Subphylum: Echinozea
Class: Holothuroidea

Physical appearance

Holothuroidea are leathery cylinder-shaped invertebrate that look wormlike. This animal can have from eight to twenty tentacles around their mouth. The mouth and the anus are located on opposite poles of the animal. They have five rows of tube feet that run along the body from the mouth to the anus. The tube feet are located in way that it gives them pentagonal symmetry.

Organ systems

Digestive systems
The digestive system is composed of the mouth, expanded pharynx the esophagus, the stomach and the intestine muscle that runs to the rectum.

Water vascular system
This system is composed of retractor and longitudinal muscles, polian vesicle and respiratory tree. The longitudinal and retractor muscles help the holothuroidea pump water throught their anus. The polian vesicle is what maintains the animal’s water pressure when they pump water. The respiratory tree is what gets the oxygen out the water and turns.

Reproductive system
This system is composed of one single gonad in the body. They eject the egg and the sperm where the fertilization takes place

Interesting Facts

These are sedentary animals which trap their food with their tentacles which are cover on mucus. They usually eat plankton but some of them are scavengers and eat organic dead matter. Holothuroidea have the ability to eviscerate their internal mass to ward of prey. These animals communicate with each other by releasing hormones in the water.

Dissection

I made the incision in the ventral part of holothuroidea which you can find where the tube feet are most evolved.