os. 
resulted in a conspicuous depression on the ventral surface of the 
caudal half, and the entire organ is somewhat laterally flattened; it 
is also somewhat smaller than the left. As it lies in place the hilus 
is on the lateral (right) aspect and a trifle ventral. so that the kidney 
must have rotated in a direction contrariwise to the normal. The 
ureter is very short, approximately 30 mm. in length, and enters the 
bladder on the right side in the usual manner. 
The A. renalis springs from the base of the A. iliaca communis 
dextra, on its ventral side, and after following this vessel for a short 
distance turns medially into the hilus, dividing there into two branches. 
The V. renalis arises from the left side of the Vena cava inferior 
just before the formation of the Vv. iliacae communes. it passes 
laterally to the left, dorsal to the aorta, then turns ventrally and 
towards the right side, crossing the A. iliaca communis sinistra near 
its origin, and on reaching the A. renalis accompanies this vessel to 
the hilus where it divides into two branches which enter caudad of 
the artery. Extending dorso-ventrally between the roots of the diverg- 
ing Aa. iliacae communes is a very slender short vein (not seen in 
figure) which forms an anastomosis between the Vv. iliaca communis 
dextra and renalis dextra. 
The present case it will be seen is a clear instance of primary 
pelvic kidney, and is essentially like such kidneys described for human 
subjects. The renal artery and vein represent early embryonic vessels 
that have been permanently retained. The ureter has failed in the 
forward growth which normally follows upon the preceding extension 
of the embryonic ureter towards the dorsal pelvic wall. This arrested 
ureter, whatever the exact nature of its cause, has manifestly in this 
case been responsible for the retention of the kidney in the pelvic 
position. 
II. Horseshoe kidney. 
This anomaly occurred in a male cat about two-thirde grown. 
At first glance the impression is obtained that there are four 
kidneys present, two smaller anterior organs and two larger posterior 
ones. This, however, is not the case, but instead, the kidney of each 
side is divided into a smaller cephalic and a larger caudal lobe. The 
four lobes thus formed lie, as a whole, slightly caudad of the normal 
level of the kidneys, across the median plane of the body. The caudal 
lobes are found to be fused together by their median sides and thereby 
is produced a form of so-called horseshoe kidney. Each lobe of the 
