4. Cebinæ.—In the typical genus Cebus the cæcum is placed laterad to the small intestine which is in direct linear continuity with the colon. The pouch is slightly convoluted toward its termination, resembling in this respect and in its position relative to the lumen of the intestinal canal, the disposition of the parts in the cynoid carnivora. Figs. 453 and 454 show the structures in two typical species, Cebus monachus and C. leucophæus.

Fig. 453.—Cebus monachus, capuchin monkey. Ileo-colic junction and cæcum; dried preparation. (Columbia University Museum, No. 26.)   Fig. 454.—Cebus leucophæus, capuchin monkey. Ileo-colic junction and cæcum. (Columbia University Museum, No. 1467.)

D. Anthropomorpha.

The cæcum is large, sacculated, provided uniformly with a vermiform appendix.

The pouch of the four anthropoid apes agrees in curve, direction, implantation of the appendix and the general arrangement of the vascular and peritoneal folds with the structure in the human subject.

1. Hylobates hoolock, Gibbon.—Figs. 455 and 456 represent respectively the ileo-cæcum of this animal in the ventral view, and from the left side with the ileum turned forward. The cæcum is a globular rounded pouch of nearly uniform diameter, only slightly enlarged to the right of the root of the appendix which arises from its lowest part and is pendent.

Fig. 455.—Hylobates hoolock, hoolock gibbon. Ileo-colic junction and cæcum; ventral view. (Drawn from Columbia University Museum preparation No. 1530.)   Fig. 456.—Drawn from same preparation as Fig. 455; view from left side, showing formation of posterior ileo-cæcal fossa.

Fig. 457.—Gorilla savagei, gorilla. Ileo-colic junction and cæcum, with ileo-cæcal folds. (Drawn from Columbia University Museum preparation No. 1543.)

(For arrangement of the ileo-cæcal folds and fossæ in this form see [p. 269].)