Fig. 373 shows the cæcum and ileo-colic junction, together with the spiral coil of the colon, in Bos indicus, the zebu, and Fig. 374 the same structures with a typical example of the spiral colon from Cervus sika, the Japanese deer; Fig. 375 is taken from a preparation of the parts in a fœtal sheep, while Fig. 376 shows the spiral colon isolated in Oryx leucoryx, the oryx.

Fig. 374.—Cervus sika, Japanese deer. Ileo-colic junction, cæcum, and spiral colon.(Columbia University, Study Collection.)

 

Fig. 376.—Oryx leucoryx, oryx. Spiral colon, isolated. (ColumbiaUniversity, Study Collection.)

Fig. 375.—Oris aries fœt, fœtal sheep. Ileo-colic junction, cæcum, andspiral colon. (Columbia University Museum, No. 1379.)

2. Suborder: Perissodactyla.

In the horse and the rhinoceros the cæcum is very large and of uniform caliber.

Fig. 377.—Tapirus americanus, American tapir. Ileo-colic junction, cæcum, and colon. (Columbia University Museum, No. 624.)

In the American tapir (Fig. 377) the large cæcum tapers at its extremity, to form a species of rudimentary appendix, resembling somewhat the corresponding structure in Dicotyles (cf. [Figs. 369] and [370]). The proximal segment of the colon is bent on itself in the form of an extensive loop with closely adherent limbs, illustrating an early stage in the development of the ruminant spiral colon (cf. [p. 233]).

3. Suborder: Hyracoidea.

Fig. 378.—Hyrax syriacus, hyrax or coney. Intestinal canal, withileo-colic junction, proximal ileo-colic cæcum, and distal paired coliccæca. (Columbia University, Study Collection.)

Fig. 379.—Elephas indicus, Asiatic elephant. Ileo-colic junction and cæcum.(Columbia University Museum, No. 995.)

Fig. 380.—Myoxus avellanarius, common dormouse. Alimentary canal. (Columbia UniversityMuseum, No. 1466.)

This suborder is formed by the single family of the Hyracidæ. In addition to their other isolated and puzzling structural peculiarities the members of this small group present a most unusual arrangement of the intestinal canal, which is unique among living mammalia. In addition to a large sacculated cæcal pouch, situated in the usual position at the beginning of the colon, the large intestine is provided further on with two supplementary elongated pointed conical pouches (Fig. 378).