Histology of the male reproductive system of the prawn Macrobrachium lanchesteri (Crustacea: Decapoda)

Abstract

The testis of the 'freshwater prawn Macrobrachium Ianchesteri consists of numerous branching lobules, bound by thin limiting membranes. There is very little inter-lobular space with indistinct blood sinuses and the lobules are filled with germ cells in different stages of development. The different regions of the vas deferens of the prawn viz., anterior vas deferens (AVD), mid vas deferens (MVD) and posterior vas deferens (PVO) , indicate structural variations reflecting the specific role of each region, in spenn transport, spermatophore formation and ejaculation. The nature of the glandular epithelium and presence of secretory material in the lumen suggest that packaging of sperms into a spermatophore is initiated in the AVO itself. The epithelial cells of the inner margin of the AVD and MVD are highly columnar. fonning a 'typhlosole'-like region. The histology of the MVD differs from that of the A VD in the presence of prominent circular and longitudinal muscle layers. Presence of copious secretory material in the MVD indicates further packaging of the  sperms. Extensive muscle layers and reduced secretory activity are characteristic of the PVO. The male hormone-producing tissue. the androgenic gland, is situated mesially in the  curvature of the ampulla, the distal end of the PVD. The histology of the gland confirms its secretory role.