CLASSIFICATION OF APLYSIA
PHYLUM :- MOLLUSCA (Unsegmented bilaterally symmetrical and provided with visceral mass, foot and mantle. )
CLASS :- GASTROPODA (Head bearing tentacles, eyes and radula; visceral hump and shell coiled due to
torsion.)
SUB-CLASS :- EUTHYNEURA (Nerve loop not twisted in figure of 8.)
ORDER :- OPISTHOBRANCHIA (Gastropods with detorsion; gills posterior of heart; shell reduced or lacking)
SUB-ORDER :- TECTIBRANCHIA
GENUS :- Aplysia (The sea hare)
GEOGRAPHICAL DISTRIBUTION
It is found in India, Asia, West Indies and on the Florida coast.
HABIT AND HABITAT
Aplysia is a marine gastropod found crawling among seaweeds. It has remarkable power of colour changes like the colour of the sunoundings. It inhabits upto a depth of 40 fathoms in uncontaminated water.
GENERAL CHARACTERSTICS OF APLYSIA
- Commonly called as sea hare.
- Body of the animal is soft, slimy, fleshy and whitish or greenish in colour. Anterior end bears head and neck.
- Animal is slug-like, with the anterior angles of the head extended into two large tentacular folds.
- Besides anterior tentacular fords, there are pair of eyes and behind eyes another tentacular fold like structure called as rhinophores.
- Mantle cavity is open on the right side with backwardly pointing ctenidium through a longitudinal slit. Anus is posteriorly located. Opening of shell sac and seminal groove is also seen.
- Foot is muscular, and elongated pointed posteriorly
- On the lateral side, there is a pair of large fleshy outgrowths called as parapodia, which project upwards and inwards to enclose visceral hump and are used as fins for swimming.
- Shell is internal and rudimentary. Opening of shell sac and spermatic seminal groove also seen.
- Animal is bisexual with a single gonoduct and a common genital opening.
SPECIAL FEATURES
Aplysia when disturbed secretes a purple fluid from the opening shell sac found in the mantle wall and it makes itself invisible to the enemy.
IDENTIFICATION
The animal has rhinophores and all above features, hence it is Aplysia.
