KIDNEYS OF REPTILES. 



539 



35: 



are lodged. In most Serpents they are unsymmetrically situated ; 

 the left in Coluber natrix, e.g., being one-fourth of its length 

 nearer the cloaca than the right kidney ; and they are loosely 

 attached to the dorsal abdominal walls. Each renal lobe is so 

 distinct that it may be regarded as a separate kidney or rennle : 

 it is reniform in Python and Boa, and is principally composed of 

 the ramifications of the renal artery, the 

 reniportal and renal veins, and the urini- 

 ferous tubules with their initial (Malpi- 

 ghian) capsules. The artery of the renule, 

 entering at the notch or ' hilum,' repre- 

 senting the pelvis, distributes its branches 

 fanwise through the middle of the sub- 

 stance: each branch, fig. 358, a, sends 

 twigs to the Malpighian capsule which 

 form within it the dilated plexus, ana- 

 logous to that in fig. 356, whence the 

 blood is returned by the efferent vessel, 

 in the direction of the arrow, to the 

 branch of the reniportal vein, fig. 358, 

 p, v : these branches being distributed 

 fan-wise over both surfaces of the flat- 

 tened renule. In this course they com- 

 municate with, or help to form, a rich 

 venous plexus, ib. p, surrounding the 

 tubuli uriniferi, ib. t, and communicating 

 with the branch of the renal or emulgent 

 vein, ib. e, v, which accompanies the 

 artery, in the mid-substance of the 

 renule. 



The tubuli, ib. t, continued, as in fig. 

 356, from the capsule of the 'Malpighian 

 body,' after some convolutions, pass to the 

 surface next which the ' body ' is placed, 

 and terminate in a branch of the ureter, 

 ur, there situated : these superficial 

 branches are dispersed fan-wise, converg- 

 ing to the ' hilum,' and are often seen 

 injected, as it were, by the opake white pultaceous urinary 

 excretion. The Malpighian bodies diminish in size and the tubuli 

 in length, towards the thin edge of the renule. 



Thus, on each superficies of the flattened renule are the radiating 

 ramuli of the ureters, ur, and reni-portal veins, pv ; whilst along 



Kidneys and small organs, Rattle- 

 snake (Grotalas). ecu 



