I.] THE FROG. 53 



They overlie the kidneys as seen, each being 

 suspended by a fold of mesentery (mesoarium). 



b. The genital ducts (oviducts) ; convoluted tubes, not 

 continuous with the ovaries, and running back to 

 open into the cloaca. Each can be resolved into 

 three segments. 



a. A middle or glandular segment ; forming the 

 conspicuous coiled portion of the tube. It will 

 be found to swell rapidly under imbibition of 

 water. 



/3. A terminal or uterine segment ; thin- walled and 

 lying immediately below and external to the 

 kidney. Examine it in relation to the cloaca; 

 it will be found to open on the apex of a pa- 

 pilla, lying side by side with its fellow, im- 

 mediately in front of the apertures of the 

 ureters. 

 Inflate it ; it is highly distensible. 



If the Frog be killed during the breeding season, 

 this segment will be seen to act as a receptacle 

 for the eggs prior to oviposition. 



y. An anterior or thin-walled segment ; short and 

 straight; it passes behind (dorsal to) the lung 

 and courses over the base of the same to open 

 into the pleuro-peritoneal cavity antero-ventrally 

 by a wide funnel-shaped mouth. 



3. In the male. 



a. The genital glands (testes], (cf. Sect. B. 2. //. a); 

 varying in size with the season of the year, and 

 each suspended by a fold of mesentery (mesor- 

 chiuui). 



