CLASSIFICATION OF LOLIGO (SQUID)
KINGDOM :- ANIMALIA (Multicellular eukaryotic organisms)
PHYLUM :- MOLLUSCA (Unsegmented bilaterally symmetrical and provided with visceral mass, foot and mantle.)
CLASS :- CEPHALOPODA (Head well developed with eyes and radula. Foot represented by arms and tentacles.)
SUB-CLASS :- DIBRANCHIA (Gills, kidneys and hearts, two each)
ORDER :- MYOPSIDA OR DECAPODA (Shell internal; 8 short and 2 long tentacles.)
FAMILY :- LOLIGINIDAE
GENUS :- Loligo (The Common Squid or Calamary)
It has cosmopolitan distribution found along the entire Pacific and Atlantic coast, China, India and U.S.A.
HABIT AND HABITAT
It is found in warm seas and in coastal shallow or deep waters. Animal metachromatic i.e. colour changing habit. Commonly called as squid having dark greyish and reddish spots.
GENERAL CHARACTERSTICS OF LOLIGO (SQUID)
- Commonly called as squid.
- Body is fleshy, dorsoventrally flattened and differentiated into 3 regions
- Anterior head containing 10 oral arms and a pair of eyes with olfactory crest.
- Middle trunk or visceral hump.
- Posterior region with lateral fins or parapodia. Parapodium is contention of mantle. Head and trunk region are separated by collar.
- Each one of 8 oral arms contain four rows of pedicellate suckers ventrally.
- Remaining 2 oral arms on each side contains six pairs of pedicellate suckers. These arms are used for capturing prey and are called as hectocotylised arms.
- In males one such arm is also modified as copulatory organ. Oral arm are modifications of the foot.
- After dissecting the animal, 2 ctenidia, 2 kidneys and 2 auricles are seen.
- Shell, internal horny and non-chambered and is used in maintenance of natural buoyancy.
- Ventral siphon is formed by the modification of foot.
- Sexes separate.
- Eggs are deposited in long cylindrical jelly masses. Loligo. attached together at one end.
- The animal ejects ink called as loligo ink in its defence. Loligo has food value. It is eaten by Chinese and Italians.
- L. vulgaris and others are noted for being attracted to lights at night; they can therefore be fished using different light-attraction methods.
The animal contains all above features and the lateral fin is restricted to posterior part, hence it is Loligo.