The androgenic gland ofM. lamerrii is situated near the seminal vesicle and along the vas deferens of the male prawns. Histologically it is made up of cords of cells which are arranged loosely. Histochemical analysis of the androgenic gland cells showed the presence of cystine/cysteins, protein bound amino acid groups. Androgenic gland ofM. lamerrii shows signs of increased secretory activity during the sexually active phase of the male. In adult prawns, eyestalk ablation results in the hypertrophy of androgenic gland. Brain and thoracic ganglion extracts also showed enhanced secretory activity of androgenic gland and corresponding gonadal activity in the male prawns.