4. Diversity In Living Organism
Phylum - Mollusca
Phylum - Mollusca :
They have soft, unsegmented body.
Body is divided into three regions (head visceral mass and ventral foot).
Outer surface is covered by a hard calcareous shell.
Respiration is by gills called ctenidia.
The sexes are usually separate.
Examples : Chiton, Pila (Snail), Unio (Fresh water mussel), Octopus (Devil fish).