Aplysia (sea hare)

Aplysia, sea hare

1. Aplysia (Sea hare) Video Prepared by -Agrani Paudel

2. Classification soft body, unsegmented, mantle body, mostly open circulation, respiration through gills or ctenidia snails, slugs, head and tentacles, asymmetrical, foot large and flat, mostly marine Exclusively ,marine, shell small, monoecious shell reduced; internal, developed parapodial lobes, head with pair of rhinophores Phylum Mollusca Class Gastropda Sub class Ophisthobranchia Order Anaspidea Genus Aplysia

3. Body is soft and lumpy with thin flexible plate like shell almost completely covered by mantle. The shell is internal

4. Head bears two pairs of tentacles, the anterior being larger and ear like, while the posterior pair is olfactory rhinophores, each bearing an eye at its base

5. Mantle cavity opens on the right side with the ctenidium pointing backwards

6. Visceral mass is raised into a prominent hump

7. Foot is broad, muscular and ventral bears a pair of lateral fleshy outgrowths Anus is at the posterior end

8. Hermaphrodite with a single generative duct and the single aperture

9. In the wall of the mantle is a gland which secretes a purple ink from within the parapodia derived from pigment within red algae. It acts as defense mechanism to ward off predators. Video

10. Habit and Habitat Sea hare is a marine gastropod found crawling in a sea weeds. It is able to change its colour according to the colour of sea weeds on which it lives. Video

11. Distribution Aplysia is found in most parts of the world from the Arctic ocean to the Antarctic. It is found in West Indies, Florida Coast, Asia, India, California, Mexico

12. Economic importance Aplysia is a highly valuable laboratory animal in the field of neurobiology in studying memory and learning behaviors. Sea hares possess the largest neurons in the animal kingdom, so it is feasible to identify the specific nerve cells responsible for specific mechanisms.