Structure of the Ovary and Mode of Oogenesis in a Freshwater Crab Sodhiana iranica

In the present study، Structure of the adult ovary and oogenetic mode were examined in the freshwater crab Sodhiana iranica. Female crabs were collected From Eelood spring located in Hormozgan province، southern Iran. In the laboratory، ovary of crabs were removed and prepared for Histological examination. An H-shaped ovary consisting of a pair of long ovarian sacs connected by a narrow bridge tube is located in the cephalothorax on the dorsal side of the stomach. A short oviduct with a seminal receptacle is connected with the posterior end of each ovarian sac، and a genital pore opens on the sternum of the sixth thoracic segment. The ovarian wall consists of a layer of ovarian epithelium that infolds to form a number of oogenetic pouches of various sizes. Each oogenetic pouch contains an egg or a relative large oocyte in its lumen. Germaria containing oogonia، very early previtellogenic oocytes، and somatic interstitial cells are located in the ovarian epithelium near the necks of the oogenetic pouches in the anterior regions of the ovarian sacs and are randomly scattered throughout the ovarian epithelium in the posterior regions of the ovarian sacs. In cross section، the germaria appear to be concentrated into a central germarial cluster in the ovarian sac. Mature eggs are ovulated from the oogenetic pouches into the ovarian lumen، transferred from the ovarian lumen into the oviducts، fertilized there by sperm stored in the seminal receptacles، and then oviposited through the genital pores. The female reproductive system is surrounded wholly and tightly by a thin، cellular، membranous sheath، which has often been mistaken as the ovarian epithelium in some decapod crustaceans.