Nervous System, Modifications of Foot, and Useful and Harmful Molluscs

M Z dash one hundred five GENERAL ZOOLOGY UNIT one TOPIC: "NERVOUS SYSTEM, MODIFICATIONS OF FOOT, AND USEFUL AND HARMFUL MOLLUSCS"

Characteristics

Anterior head

Ventral foot

Systematic Classification of Molluscs:

There are seven classes of phylum Mollusca

Class one. Aplacophora (shell less deep sea marine molluscs) Order one: Neomeniooidea e.g. Neomentoia, Lepidomenia Order two: Chaetodermatoidea e.g. Chaetoderrma, Prochaetoderma

Class two. Polyplacophora (elongate oval with dorsal shell of eight plates) Order one: Lepidopleurida e.g. Lepidopleurus, Hanleya etc. Order two: Chitonina e.g. Chiton, Choneplex etc.

Class three. Monoplacophora (one plate shell) e.g. Neopilina Class four. Gastropoda (Gr. gaster equals belly plus podos equals foot, coiled shells) e.g. Pila, Bulla, Clione

Class five. Scaphopoda (tusk shells) e.g. Dentallium

Class six. Pelecypoda (having two shells) e.g. Mytilus, Arca

Class seven. Cephalopoda (completely merged head and foot with rings of arms surrounding head) e.g. Sepia, Loligo, Spirula, Octopus, Nautilus