538 



ANATOMY OF VERTEBRATES. 



355 



Malpighiau body, Newt. CCLXXXVI. 



356 



vessel dilates on entering, forms a few coils, again contracts, and 



becomes the efferent vessel. 1 In the 

 Frog the kidneys present a more 

 compact form ; they are flattened, 

 subelongate, with a convex outer 

 border and a nearly straight inner 

 one, fig. 331, K, k. They are situated 

 at the pelvic end of the abdominal 

 cavity behind the rectum and allantoid 

 bladder : the peritoneum covering 

 only their sternal surface. The renal 

 capillaries, derived from the reniportal 

 vein, ib. K, ramify through the gland to 

 reach the Malpighian capsule, fig. 356, 

 f: in the specimen figured, by Bowman, 2 

 under the magnifying power of 320 dia- 

 meters, the part where the capillaries enter (near t) is obscured by 



an uriniferous tube. On enter- 

 ing, the capillary enlarges and 

 forms a few coils, m, which lie 

 bare in the capsular cavity. The 

 lemma begins to receive an epi- 

 thelial lining at f, f, which 

 increases in thickness to the neck 

 of the tubule, d, d, and is covered 

 by cilia : these may maintain 

 their motions hours after the 

 death of the Frog. The urini- 

 ferous tubules form by succes- 

 sive unions the ureter, which 

 opens into the urogenital com- 

 partment of the cloaca, opposite 

 the orifice of the large bifid al- 

 lantoid bladder, the contents of 

 which are mainly water. 



In Serpents the kidneys, fig. 

 357, t, t, partake of the usual 

 elongated form of the viscera, 

 and are subdivided into numerous 

 flattened, overlapping lobes, so 

 as readily to accommodate them- 

 selves to the flexuosities of the 



body, rrog. cxxxvn. l^rt of the trunk in which they 



1 cxxxvir. 2 Ib. 



