15 



siderably in size in different individuals. In the present specimen it was 

 49 cm. in length and 15.5 cm. in width. In another case it measured 62 cm. 

 by 18 cm. The dorsal extremity lies under the vertebral ends of the last 

 two ribs ; sometimes this end of the spleen extends back as far as to the mid- 

 dle of the first lumbar transverse process. The ventral extremity is oppo- 

 site the costo-chondral junction of the eighth rib ; not infrequently, how- 

 ever, this extremity does not extend so far ventrad. The parietal surface 

 of the spleen is convex and is in contact with the diaphragm only, except 

 possibly a very small part of its dorsal portion. The visceral surface is 

 concave and is related principally to the rumen, PL VI, 27. Its ventral 

 end is usually in contact with the reticulum for a distance of 5 cm. more or 

 less. The dorsal part of the spleen is attached to the left cms of the dia- 

 phragm and to the rumen by connective tissue and reflected peritoneum. 

 The ventral end is free or unattached for a distance of 12 to 15 cm. About 

 one half of the visceral surface of the spleen is attached directly to the ru- 

 men by connective tissue and is not covered with peritoneum, PI. VI. Sim- 

 ilarly there is a non-peritoneal area of two to three centimeters average 

 width on the parietal surface along the dorsal half of the cephalic border of 

 the spleen. The area for percussion of the spleen is well shown in PI. V. 

 In this connection it should be noted that the spleen is overlapped to about 

 one half of its width by the left lung, the diaphragm intervening between 

 the two organs. 



The kidneys of the cow are distinctly lobulated. The lobules are of un- 

 equal size and vary in number from eighteen to twenty- three, more or less. 

 The right kidney is elongated and flattened dorso-ventrally. Its average 

 dimensions are 21 cm. in length, 12 cm. in width and 4 to 6 cm. in thickness. 

 It commonly lies ventral to the last rib and the transverse processes of the 

 first two lumbar vertebrae ; in some cases it extends as far as the trans- 

 verse process of the third lumbar vertebra. The dorsal surface is in contact 

 with the sublumbar muscles. The ventral surface is related to the liver, 

 pancreas, right adrenal, duodenum and the large intestine. The right kidney 

 did not touch the rumen ; the aorta, vena cava and crura of the diaphragm 

 intervene between the two. 



The left kidney in adult cattle and sheep occupies an unexpected position. 

 Instead of lying wholly to the left of the median plane as it does in non- 

 ruminant mammals and in the young (calf and lamb) of ruminants, it is 

 situated either partially or wholly to the right of the median plane, PI. IV, 

 27 ; PI. VIII, 14. This is apparently dependent upon the extent of re- 

 pletion of the rumen. The left kidney is situated considerably farther 

 caudal than the right. It extends from opposite the caudal edge of the 



