In the typical lemurs the caecum is long, frequently terminating in a pointed appendage. The proximal segment of the colon is looped and coiled, resembling the spiral colon of the Ungulates and Rodents. Fig. 420 shows the caecum of _Nycticebus tardigradus_, the slow lemur, with the typical appendage, and Fig. 421 shows the spiral arrangement of the proximal colon immediately beyond the ileo-colic junction in the same animal. Fig. 422, taken from another specimen of the same animal shows the caecum, appendix and spiral colon. Figs. 423, 424, 425 illustrate the structure of the parts in three other members of the group, _Lemur macaco_, _Lemur mongoz_ and _Otolicnus crassicaudatus_, all showing terminal reduction of the caecal pouch and tendency to spiral coiling of the proximal colon. In _Tarsius spectrum_ (Fig. 426) the caecum is relatively well-developed, but forms a simple pouch of uniform diameter, without terminal reduction. [Illustration: FIG. 420.--_Nycticebus tardigradus_, slow lemur. Ileo-colic junction, caecum, appendix, and colon; dorsal view. (Columbia University Museum, No. 20/1468.)] [Illustration: FIG. 421.--_Nycticebus tardigradus_, slow lemur. Same preparation as Fig. 420; ventral view, showing spiral coiling of proximal colon. (Columbia University Museum, No. 20/1468.)] [Illustration: FIG. 422.--_Nycticebus tardigradus_, slow lemur. Ileo-colic junction, caecum, appendix, and spiral colon. (Columbia University, Study Collection.)] [Illustration: FIG. 423.--_Lemur macaco_, lemur. Ileo-colic junction and caecum. (Drawn from preparation.) (Columbia University Museum, No. 1623.)] [Illustration: FIG. 424.--_Lemur mongoz_, lemur. Ileo-colic junction and caecum. (Drawn from preparation.) (Columbia University Museum, No. 1473.)] [Illustration: FIG. 425.--_Otolicnus crassicaudatus_, galago. Ileo-colic junction and caecum. (Drawn from preparation.) (Columbia University Museum, No. 1626.)] [Illustration: FIG. 426.--_Tarsius spectrum_, spectre lemur. (Drawn from preparation.) (Columbia University Museum, No. 1521.)] 2. Suborder Anthropoidea. A. CYNOMORPHA. =1. Cynocephalus.=--The baboons have a well-developed capacious caecum. The apex of the pouch is usually blunt and rounded, or only slightly pointed. The caecum is sacculated, conforming in structure to the rest of the large intestine. Two low vascular folds or ridges, a ventral and a dorsal, carry the ventral and dorsal caecal branches of the ileo-colic artery. The intermediate non-vascular fold is large, frequently fused with the dorsal vascular fold (cf. p. 264). Figs. 427-433 show the structures in _Cynocephalus sphinx_, _porcarius_, _babuin_, _anubis_ and in _Cercopithecus pogonias_, _sabaeus_ and _campbellii_. [Illustration: FIG. 427.--_Cynocephalus sphinx_, Guinea baboon. Ileo-colic junction and caecum. (Columbia University Museum, No. 1082.)]