Journal of the Marine Biological Association of India

Structutre and chemical composition of the periostracum of Perna viridus.

Volume 26 Issue 1&2

Sowmini Balakrishnan

Abstract

The periostracum of Perna viridis at an early growth stage showed the presence of three distinct layers with varying structural and chemical features: outer yellow, middle broad light green with vertical striations and innermost yellow layer. At a later growth stage there is an increase in thickness of the middle layer, with three well-marked regions comprising a central green coloured part (in Mallory takes up red colour) which is vacuolated (containing inclusions) and outer and inner parts which are yellow coloured (refractile to stains).

The outermost layer of the periostracum of an animal in a late growth stage becomes amber coloured and resistant to the action of mineral acids indicative of the sclerotized nature. The chemical characteristics of the middle layer differ markedly from those of the outer and inner layers and shows similarity to that of the epicuticle of arthropods.

Date : 31-12-1984