CLASSIFICATION OF CHITON
PHYLUM :- MOLLUSCA (Unsegmented bilaterally symmetrical and provided with visceral mass, foot and mantle. )
CLASS :- AMPHINEURA (Head reduced, without eyes and tentacles, nervous system without definite ganglia. )
ORDER :- POLYPLACOPHORA (Foot flat and mantle secretes 8 shell plates.)
GENUS :- Chiton (Sea mouse)
Chitons are found in all parts of the world in shallow waters, few species live in deep sea
HABIT AND HABITAT
Chiton is a marine and sluggish slow moving animal, attached to rocks, empty shells, corals and under stones between tidemarks. It is mostly noctumal and remains concealed under rocks during day-time. It rolls its body when disturbed. It is a vegetable feeder and its food consists of algae and diatoms.
GENERAL CHARACTERSTICS OF CHITON
- Commonly called as sea mouse, measuring about 1 to 5 cms.
- Body is elliptical, bilaterally symmetrical and dorsoventrally flattened and is differentiated into a small, indistinct head, a large flat foot and a dorsal mantle forming a roof-like covering.
- Head contains ventral mouth and labial palps. Below head is sole of foot ventrally.
- Eyes and tentacles are absent. Mouth and anus are opposite ends.
- Dorsal side of mantle contains a linear series of 8-calcareous overlapping plates marked with lines of growth. Sides of mantle form mantle girdle.
- Several pairs of bipectinate ctenidia are found in a complete rows on either side of the body and lie in a mantle groove between foot and ventral side.
- Plates are surrounded and kept in place by a muscular integumental fold called girdle.
- Entire periphery of the mantle girdle contain small calcified tubercle or spicule.
- Exposed part of the plate is called as tegumentum and overlapping part is called as articulum.
Sometimes Chiton is eaten by man. The foot is called as sea beal.
Contains 8 calcareous plates dorsally and all above features hence it is Chiton.