URINOGENITAL ORGANS 



357 



often penetrated by deep furrows and clefts in which the veins 

 lie embedded ; posteriorly they may fuse together in the middle 

 line, as in Lizards. 



There is not always a perfect symmetry between the organ 

 of either side, and this is most marked in Snakes, in which the 



An 



FIG. 283. MALE URINOGENITAL APPARATUS OF HERON (Ardea cinerea). 



JV, kidneys ; Ur, ureter, opening into the cloaca (O) at Sr ; Ho, testis ; Ep, epi- 

 didymis ; Vd, vas deferens, which opens at Vd l op a papilla in the cloaca : 

 V, V, furrows on the ventral surface of the kidney in which veins lie em- 

 bedded ; Ao, aorta ; BF, bursa Fabricii, which opens into the cloaca at BF 1 . 



greatly tabulated kidneys, like those of limbless Lizards, are 

 elongated, narrow, and band-like, in correspondence with the 

 form of the body. 



A urinary (allantoic) "bladder arising from the ventral wall of 

 the cloaca, is present in Lizards and Chelonians ; it is more or less 

 bilobed. A bladder is wanting in Snakes, Crocodiles, and Birds. 



