284 LABORATORY MANUAL FOR VERTEBRATE ANATOMY 



At the anterior end of the pleuroperitoneal cavity it becomes of a more delicate 

 texture and is fastened to the lateral wall. Here it opens by a funnel-shaped 

 opening, the ostium; the dorsal rim of this is fastened to the body wall, but the 

 ventral rim is free and can be lifted to expose the opening. Trace the oviducts 

 posteriorly to the cloaca. They enter this one to each side of the large intestine. 

 Cut the cloaca open by a lateral slit extending up into the intestine. Note the 

 papillae by which the oviducts open into the cloaca. 



The kidneys are long slender organs extending from the cloaca forward 

 along the dorsal surfaces of the oviducts. They are retroperitoneal. They are 

 mesonephroi. The duct, the Wolffian or mesonephric duct, lies along the lateral 

 border of each kidney. It is very delicate in the female and difficult to locate. 

 It proceeds to the cloaca into which it opens to the dorsal side of the oviduct. 

 In tracing it make a cut along one side of the cloaca, freeing the cloaca from the 

 body wall. 



Note the urinary bladder extending from the midventral region of the 

 cloaca. Find its opening into the cloaca. 



Draw, showing ovaries, kidneys, their ducts, and the opened cloaca. 



2. The male urogenital system. — The testes are a pair of elongated bodies 

 situated to the sides of the small intestine. Each has a mesentery, the mesor- 

 chium. Dorsal and lateral to each testis is the long brown kidney, larger than 

 in the female. The kidney is a mcsonephros. Along the lateral border of the 

 kidney is a conspicuous coiled duct, the Wolffian or mesonephric duct. This also, 

 as in vertebrates in general, acts as the sperm duct. By holding up the mesor- 

 chium to the light note the delicate ducts, the vasa efferentia, which cross it into 

 the kidney. The sperm pass through the tubules of the kidney and into the 

 Wolffian duct. Trace the latter to the cloaca. Open the cloaca by a slit to 

 one side of the median line carrying the slit into the large intestine. The openings 

 of the Wolffian ducts into the cloaca are generally difficult to locate, owing to 

 their small size. Note the urinary bladder and its opening into the ventral 

 cloacal wall. 



Draw, showing testes, kidneys, Wolffian ducts, and opened cloaca. 



D. THE UROGENITAL SYSTEM OF THE TURTLE 



Remove the digestive tract, if not already done, leaving the large intestine 

 in place. 



1. The female urogenital system. — This consists as usual of a pair of ovaries 

 and a pair of Miillerian ducts or oviducts. The ovaries have already been noted 

 as large baglike bodies in the posterior part of the pleuroperitoneal cavity. 

 They usually contain yellow eggs in various states of development. Each ovary 

 is supported by a mesentery, the mesovariiun. Along the posterior border of 

 each ovary runs the oviduct, a large white coiled tube, supported by the mesotu- 

 barium. Trace the oviduct forward and find the ostium; this lies in the mesen- 



