204. 



of the Hare and other Rodents ,hQ\ng sacculated, and distended with 

 a blackish pultaceous matter ; but in form one would compare it 

 rather with that of the Tapir, its magnitude arising more from its 

 breadth than its length. Its length from the orifice of the ileum is 3 

 inches, its circumference 8 inches. The colon gradually diminishes 

 as it leaves the cacum, 4 inches from which its diameter is nearly that 

 of the small intestines : the dilated part of the colon is bent in a sig- 

 moid form, and the remainder is convoluted on a broad mesocolon, 

 and at a distance of 2 feet from the dilated part (when unravelled) 

 terminates between two conical cceca in a second dilated intestine. 

 Each of these singular caca was an inch and a half in diameter at its 

 base, and gradually contracted till it terminated in a glandular ver- 

 miform appendage about half an inch long, and 2 lines in diameter. 

 The intestine continued from these was 3 inches in diameter, but also 

 gradually contracted, so that at a distance of 6 inches it also became 

 as small as the small intestines. The whole length of this intestine, 

 the " intestinum bicorne " of Pallas, or second colon, was 2 feet 6 

 inches in length ; making the length of the whole intestinal canal, 

 exclusive of the caca, 9 feet 4 inches, or about six times the length 

 of the animal. Nothing in particular was observed either in the first 

 or second divisions of the colon ; but the contents of the latter were 

 much drier than those of the former, and were collected into detached 

 fibrous masses, or scyhala. Notwithstanding the complexity of the 

 intestinal canal, it is suspended from a single continuous duplicature 

 of the peritoneum advancing from the bodies of the vertebrce and ex- 

 tending from the beginning o^ i\\Q jejunum to the rectum. 



" In looking through the Vertebrata for an analogous formation of 

 the intestinal canal, we shall find the Hyrax standing almost alone 

 in this respect : among the Mammalia it is only in a few of the 

 Edentate species that the double cacum is to be met with, as, 

 e. g. Mijrmecophaga didactyla, Linn., and Dasypus 6-cinctus, Linn.; 

 whilst in Birds, although the double ccecum more generally prevails, 

 yet an additional single ccBCum, anterior to these, has only been 

 found in a few species. This structure, however, completes the 

 analogy, quoad the number of ccBca, but with respect to function the 

 cases are widely different ; the single anterior ccecum of Hyrax evi- 

 dently performs an important part in digestion, while in the Bird it 

 exhibits merely a trace of a structure peculiar to embryonic life. I 

 should consider, however, the double ccecum of Hyrax as indicating 

 an affinity to the group which intervenes, in the system of Cuvier, be- 

 tween the order it was originally placed in, and the one to which that 

 great naturalist has transferred it. And it is interesting to find that 

 while the /acies of Hyrax so far simulates that of a Rodent as to have 

 deceived the older naturalists, and to have concealed from them those 

 unerring indications of its alliance with the Pachydermata which the 

 osseous system exhibits, yet that Nature, as if in confirmation of her 

 abhorrence to the saltus, had left in the internal structure of this sin- 

 gular animal an impression borrowed from the type of the Edentata. 



" Although the stomach of some of the Rodentia, as the common 

 Rat, and of the Edentata, as the Manis, exhibits a partial cuticular 



