1. Chiton is a marine and sluggish slow-moving animal, attached to rocks, empty shells, corals and under stones between tidemarks. It is mostly nocturnal 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.
2. Chitons are found in all parts of the world in shallow waters, few species live in deep sea.
3. Commonly called as sea mouse, measure about 1 to 5 cms.
4. 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.
5. Head contains ventral mouth and labial palps. Below head is sole of foot ventrally.
6. Eyes and tentacles are absent. Mouth and anus are opposite ends.
7. Dorsal side of mantle contains a linear series of 8-calcareous overlapping
plates marked with lines of growth. Sides of mantle form mantle girdle.
8. Several pairs of bipectinate ctenidia are found in complete rows on either side of the body and lie in a mantle groove between foot and ventral side.
9. Plates are surrounded and kept in place by a muscular integumental fold called girdle.
10. Entire periphery of the mantle girdle contains small calcified tubercle or spicule.
11. Exposed part of the plate is called as tegumentum and overlapping part is called as articulum.
Source:
1. Practical Zoology Invertebrates by S.S.Lal. 2. A Manual of Practical Zoology Chordates by Dr. P.S. Verma.
