524 Proceedings of Royal Society of Edinburgh. [srss. 
this blunt ridge is that the ventral surface has three slopes — mesial, 
lateral, and caudal in position. The mesial and caudal slopes and the 
caudal part of the lateral slope are in contact with the colon. The 
remainder of the lateral slope is related to the spleen and pancreas 
(fig. 3). The lateral (convex) border is comparatively narrow ; 
the mesial border is more rounded. The caudal extremity of this 
kidney is much larger than the cephalic, which is flattened for the 
adrenal body. 
The right kidney is more convex on its dorsal surface than the 
left ; and along this surface is a blunt ridge passing from one end 
to the other. The ventral surface is very convex, especially in its 
cephalic half ; the rest being more flattened. So much of the 
lateral border as is in contact with the liver is thick and rounded ; 
but caudal to this the border is much sharper. The mesial border 
is both straighter and narrower than the corresponding border of 
the other kidney. There is no great disparity in the size of the 
two extremities, as is the case in the left kidney. The cephalic 
end is blunt, rounded, and thick ; the caudal end being rounded 
transversely, but flattened dorso-ventrally. 
Adrenals. — There is some dissimilarity in the shape of the two 
adrenals ; but the unlikeness is not nearly so notable as we shall 
see obtains in Lagothrix. The right adrenal fits into an interval 
circumscribed by the caudate lobule and the right lateral lobe of 
the liver and the right kidney. It is conical in form, with a 
concave base — applied to the kidney — and a bluntly pointed 
apex. The left adrenal is flattened in a dorso-ventral direction. 
Its apex is much blunter than that of the right, and its base is 
flat to accommodate itself to the flattened cephalic extremity of the 
left kidney. 
Lagothrix humboldti. 
(Esophagus. — As in Cercocebus , there is practically no abdominal 
part of the oesophagus. 
Stomach. — In its external form the stomach of Lagothrix is 
somewhat simpler than that of Cercocebus , inasmuch as there is 
no sharp division into a saccular fundus and a tubular body and 
pyloric portion. At the same time there is a curious, somewhat 
saccular diverticulum dorsal to and to the left of the entrance 
