The nervous system in Molluscs (Figs. 16.68-16.70) presents numerous diversities. It exhibits gradual coming up of complexities from simple to complex which can be marshalled into one perspective—the nervous co-ordination. Prior to the description of the nervous system in different forms of Molluscs a basic plan of the Molluscan nervous system is to be considered first. Hypothetical Plan of Molluscan [...]
1. Skin and mantle. 2. Molluscan gills or ctenidia or branchiae and 3. Lungs or pulmonary sac. The outer covering of the body (skin) and mantle usually act as accessory respiratory organs. 1. Skin and Mantle — as Respiratory Organs: Skin appears to be the simplest type of respiratory structure encountered in Molluscs. It acts as a respiratory organ in [...]
1. Edible Molluscs: (i) Edible Oysters: From ancient times the Romans and Greeks used the oysters as a main dish in their meals. The Red Indians were great oyster eaters. The maximum amount of oyster meats are collected from two genera— Ostrea and Crassostrea, which belong to the family Ostreidae and class Bivalvia. In Japan, United States and Europe over [...]