450 DISSECTION OF THE PIGEON. 



nephric or Wolffian duet : in the female the oviduct is formed 

 from the Miillerian duct. In both sexes the kidneys and 

 ureters of the adult are formed on each side from the hindmost 

 division of the kidney of the embryo, i.e. the metanephros, 

 and the metanephric duet. 



A. The Male Pigeon. 



1. The renal system. 



a. The kidneys are a pair of solid three-lobed bodies, 



lodged in cavities bounded by the iha and 

 sacrum, immediately behind the lungs. Their 

 ventral surfaces are covered by peritoneum. 

 There is no distinction between cortical and 

 medullary portions, and no pelvis. 



b. The ureters are a pair of straight narrow tubes. 



Each arises in the substance of the anterior lobe 

 of its kidney, emerges between the anterior and 

 middle lobes, and runs backwards along the inner 

 side and ventral surface of the middle and posterior 

 lobes, and then straight back to the dorsal wall of 

 the cloaca. 



Slit up one of the ureters, and follow it into the anterior 

 lobe of the kidney, noting the openings of smaller ducts into 

 it at intervals along its length. 



c. The adrenals are a pair of small elongated yellowish 



bodies, attached to the ventral surface of the 

 anterior ends of the kidneys, alongside the iliac 

 veins. They have no physiological connection 

 with the kidneys. 



2. The reproductive system. 



a. The testes are a pair of oval bodies, attached by a 



fold of peritoneum to the inner borders of the 

 anterior lobes of the kidneys, and lying in contact 

 with their ventral surfaces. 



b. The vasa deferentia emerge from the inner sides 



of the posterior ends of the testes, and run back 



