286 LABORATORY MANUAL FOR VERTEBRATE ANATOMY 



The kidneys were previously identified as flattened lobed bodies fitting 

 against the posterior wall of the pleuroperitoneal cavity. Each testis is a yellow 

 spherical body attached to the ventral face of the kidney by the mesorchium. 

 Lateral and posterior to the testis is an elongated, dark-colored coiled body, the 

 epididymis. The testis is connected to the anterior part of the epididymis 

 by the minute vasa ejfferentia which run in the mesorchium. The vasa efferentia 

 and this portion of the epididymis are the remnants of the mesonephros. The 

 remainder of the epididymis constitutes the male duct or vas deferens (Wolffian 

 duct}. Remove the peritoneal covering of the epididymis and uncoil the vas 

 deferens. Trace it to the cloaca. It enters anterior to and at the base of the 

 bulb of the penis. 



Next cut open the cloaca, inserting the blade of the scissors into one corner 

 of the anus and cutting far to one side to avoid injuring the penis. Spread 

 apart the cloacal walls and study the penis. It consists of two spongy ridges, 

 the corpora cavcrnosa or cavernous bodies, in the ventral wall of the cloaca. 

 Between these folds in the midventral line is a deep groove, the urethral 

 groove, which in the natural condition is practically converted into a tube by the 

 approximation of the cavernous bodies. The urethral groove terminates caudad 

 at the base of a heart-shaped projection, the glans of the penis. The anterior 

 ends of the cavernous bodies form the bulbs already noted, which project forward 

 into the coelom at the sides of the stalk of the bladder. The bulbs are filled 

 with blood which they receive from the internal iliac vein. All parts of the penis 

 are highly spongy and vascular. In the sexual act the blood from the bulbs 

 rushes into the spongy spaces of the cavernous bodies and the glans, erecting 

 them, and causing the cavernous bodies to come in contact above the urethral 

 groove, converting the latter into a canal for the passage of the sperm. 



The kidneys are metanephroi, and their ducts the metanephric ducts or 

 ureters. The ureter will be found immediately to the dorsal side of the epididymis 

 which should be removed. The ureter is a short straight tube proceeding to 

 the cloaca, into which it opens just anterior to the opening of the vas deferens. 

 The two openings will be found at the sides of the anterior beginning of the 

 urethral groove. 



Find the openings of the accessory bladders, the urinary bladder, and the 

 rectum into the cloaca. The latter is dorsal to the urogenital openings. 



Draw the male urogenital system with open cloaca. 



E. THE UROGENITAL SYSTEM OF THE PIGEON 



i. The female urogenital system. Remove the digestive tract, leaving the 

 large intestine in place. In adult birds there is a single ovary and oviduct on the 

 left side. The right ovary and duct are present in the embryo but almost 

 entirely disappear before hatching. The ovary is a mass containing eggs of 



