54 INTRODXJCTION. 



of the kidney, and are nearly tliree times as long as 

 broad. 



In Alytes obstetricans the testes are subspherieal or 

 shortly oval, yellow, usually more or less sprinkled 

 over with black pigment. There are two vasa effe- 

 rentia, which do not open into the kidney but pass into 

 the Miillerian duct, which functions as a seminal duct 

 distinct from the ureter, and bears, as a diverticulum, 

 a large strongly pigmented vesicula semi ids. 



In Pelobates fuscns the testes are oval, flattened, 

 their length one-third to three-fourths that of the 

 kidneys, the anterior extremity of which they nearly 

 reach ; they are yellow, rarely feebly pigmented. A 

 vesicula sevviiiis is absent. 



Pelodytes punctatus agrees very closely with the 

 preceding. The testes are small, measuring only one- 

 third the length of the kidney, and much pigmented, 

 nearly black. 



In Bufo vulgaris the testes are yellow, sometimes 

 more or less pigmented, elongate, cylindroid or 

 flattened, two or three times as long as broad, one- 

 half to three-fourths the length of the kidney, to the 

 anterior extremity of which they iisually do not 

 extend. A vesicula seminis is absent. In B. viridis 

 the testes may be shorter, more oval, or cylindroid, 

 and more than half as long as the kidney; they are 

 moi'e or less strongly pigmented, sometimes entirely 

 black, and do not extend to the anterior extremity 

 of the kidney. B. calamita has the testes elongate, 

 and, as in B. viridis, they are situated opposite the 

 middle of the kidney; they are so strongly pigmented 

 as to appear entirely or nearly entirely black. 



In liyla arhorea the testes are yellow, and resemble 

 those of Bufo vnlgaris in size, form, and position. A 

 vesicula seviinis is present. 



In Bana esculenta the testes are yellow or orange, 

 short, oval, not half the length of the kidneys, to the 

 middle of which they are attached ; the vesicula 

 seminis is confounded with the ureter, which is of 



