Page 2 - 2.Lesson Notes-Animalia 2
P. 2
Examples: insects, scorpions, spiders, millipedes, centipedes, crabs, lobsters etc
Mollusca
• They are bilaterally symmetrical, with a reduced coelomic cavity and little
segmentation.
• They have an open circulatory system and kidney like organs for excretion.
• Body is soft and usually enclosed in a shell. The shell may be external or
internal.
• They show the presence of Foot, Mantle and Mantle cavity.
• Muscular foot helps in locomotion.
• Examples: pearl oysters, bivalves, sepia, octopus, snail, slug etc.
Echinodermata
• They are spiny skinned and free-living.
• Exclusively marine.