This study deals with the histomorphology of the mesonephros in male and female Neurergus microspilotus. The slender and narrow kidneys are positioned in the retro peritoneal position up against the ventral aspect of vertebral column and may extend the length from the esophagus-stomach junction to cloaca. The kidney in both sexes is composed of sexual (anterior) and pelvic (posterior) parts.

The duct of sexual kidney is a narrow duct which is lying alongside its lateral edge. In the female, it is connected to the ureters and then the duct of definitive kidney. Before entering the cloaca, two ureters are joined together and open to the apex of the cloaca. In the male, after entering the sexual kidney, the sperm leave the testis through efferent ducts, then these ducts join together and eventually form Bidder’s duct.

The Bidder’s duct joins the Bowman’s capsule of the nephrons in the sexual kidney and the nephrons make collecting ducts which are filled with both sperm and urine. After leaving the kidney, all the collecting ducts are connected to the Wolffian duct. Wolffian duct joins the ureters (merge from definitive kidney) just before entering the cloaca.

Based on serial paraffin sections, nephrons consist of a filtration unit, the Malpighian corpuscle, and a renal tubule, which can be divided into 4 morphologically distinct segments: proximal tubule (first and second segment), distal tubule, and collecting tubule. Collecting tubules merge and form a branch system that opens into collecting ducts.

This research has been published in AHR,which was supported by Chengdu Institute of Biology.