STUDIES IN THE PERITONEUM. 
539 
GENERAL OBSERVATION OF THE SQUIRREL’S 
(RODENTIA) PERITONEUM. 
The squirrel’s abdomen being open, the mighty cascum 
lies curled up on the left side of the left iliac fossa. The two 
(double-barreled) double colons lie on the right side, parallel 
to each other and to the body, one anterior (upper), and the 
other posterior (lower). The one nearest to the cascum is 
some three inches in a large gray squirrel, and the next is 
two inches, i.e., one is about two-thirds as large as the other. 
The use of these loops of colon, held in a single mesentery, 
and fed by a single artery, must have been originally for the 
same purpose as the enormous cascum, viz.: secondary stom¬ 
ach where the food could tarry and be fully digested. The 
apparent danger of such double colons and such free, mobile 
casca and added mesenterium commune is volvulus, and Dr. 
Baker, professor in the Chicago Veterinary College, informs 
me that this is just what often occurs in the horse. 
