Histological and histochemical studies on regeneration and tissue differentiation in the crab Menippe rumphii (Fabricius) (Crustacea: Brachyura)

Abstract

In the process of regeneration the crab secretes an outer three-layered fibrous exoskeleton, consisting of outer thin parenchymatous vacuolated layer, an elastin layer, and a collagen layer. The origin and synthesis of these layers have been discussed. Similarly a two-layered inner cuticle is also secreted during the process of regeneration. Together with this, tissue differentiation takes place inside the growing limb bud. The rôles of the cells responsible for the secretion of the outer and inner cuticular layers have been discussed. Various histochemical tests have been employed to study the chemical nature of the cuticular layers, connective tissue cells, tegumental glands, and haemocytes. Two types of connective tissue cells and four types of haemocytes were identified. The rôles of the haemocytes, tegumental glands, and connective tissue cells in tissue differentiation are also discussed.