U BINARY ORGANS. 



309 



p. 310) project ; on the summits of these the urinary tubules open 

 in varying number (between Pr and Co). The calyces are continu- 

 ous with a large cavity in the widened portion of the ureter called 

 the pelvis (Pi), and from this the ureter (Ur) passes backwards to 



An 



FIG. 242. MALE URINOGENITAL APPARATUS OF HEEON (Ardea cinerea). 



N, kidneys ; Ur, ureter, opening into the cloaca (Cc) at Sr ; Ho, testis ; Ep t epi- 

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

 V, V, furrows on the ventral surface of the kidney in which veins lie embedded ; 

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



open into the bladder on its dorsal side, sometimes nearer the apex, 

 sometimes towards the fundus. 



The urethra, arising from the bladder, is always short in the 

 female, while in the male it is drawn out into a long tube which 

 extends through the penis, and is lined by erectile tissue (corpus 

 spongiosum) (comp. p. 329). 



The definitive kidney (metanephros) is greatly lobulated in 



