ABDOMINAL VISCERA. 21 



a. The ureters, or ducts of the kidneys, are a pair of white 

 tubes arising from the outer edges of the kidneys at 

 about a quarter of their length from their hinder ends, 

 and running back to open into the dorsal wall of the 

 cloaca, oi3posite the opening of the bladder. 



In the male frog a pouch-like dilatation, the 

 vesicula seminalis, is present on the outer side of 

 each ureter, close to its opening into the cloaca. 



3. The Spleen is a small round dark-red body lying in the 

 mesentery, opposite the commencement of the large intestine. 



