Question

Give four general characters of phylum Mollusca. Write down two examples.

Answer 1

General characteristics of phylum Mollusca:
(i) They have a soft, bilaterally symmetrical body with little segmentation and without appendages. Body cavity is haemocoel.
(ii) Body is divisible into an anterior head, a ventral foot and a dorsal visceral mass. The entire body is covered by a thin fold of skin called mantle, which secretes a hard calcareous shell of one or more pieces.
(iii) Respiration occurs via gills, mantle or a "lung" of the mantle.
(iv) Sexes are usually separate.
Examples: Chiton and Pila.