EXCRETORY SYSTEM. 



577 



Excretory system. The paired kidneys are elongated 

 organs situated dorsally and posteriorly beside the urostyle. 

 The waste products which they filter out of the blood pass 

 backward by two ureters which open separately on the 

 dorsal wall of the cloaca, and are not directly connected 

 with the bladder. The ureter or Wolffian duct is seen as a 

 white line along the outer side of each kidney ; in the male 



FlG. 281. Urogenital system of 

 male edible frog. After Ecker. 



FIG. 282. Urogenital system of 

 female frog. After Ecker. 



/!/>., Fatty bodies; v.c., vena cava ; ovd. , Opening of oviduct ; ov., ovary; 



T., testis ; K., kidney; iv.d., Wol- 

 ffian duct ; cl., cloaca ; Bl., bladder. 



f.b., fatty body; K., kidney; Ut., 

 uterus ; Ur., opening of ureters into 

 cloaca (cl.), in front of the openings 

 of the oviducts. 



it functions also as the duct of the testis. On the ventral 

 surface of each kidney is a longitudinal yellowish streak, 

 which is an adrenal gland of unknown significance, and 

 little spots mark ciliated apertures or nephrostomes, which 

 remain as communications between the abdominal cavity 

 and the renal veins, though they are originally connected 

 with the urinary tubules. There are also, as in higher 



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