318 



COMPARATIVE ANATOMY. 



Chelonians they are broad, while in Snakes and snake-like Lizards 

 they are more elongated. In the latter cases, as well as in other 

 Lizards, they are asymmetrical, so that the organ of one side comes 



Ot 



FIG. 249. FEMALE URINOGENITAL APPARATUS OF Lacerta muralis. 



N, kidneys ; Ur l , apertures of the ureters into the cloaca (Cl) ; B, urinary bladder ; 

 2? 1 , neck of the latter (cut open) ; M, rectum ; S 1 , opening of ivetum into the 

 cloaca ; Ov, ovaries ; t, remains of mesonephros ; Od, oviducts, which open into 

 the cloaca at Od 1 ; Ot, abdominal openings of oviducts. 



to lie in front of that of the other. More room is thus obtained 

 for the development of the ovaries, and, in cases where the eggs 

 are very large, the organ of one side tends to disappear ; in Birds, 



