PROF. OWEN ON THE ANATOMY OF THE INDIAN RHINOCEROS. 43 
fibres in the rectum and those of the external sphincter was well-marked, the latter pre- 
senting the striated character of true voluntary muscles. 
The herbivorous Mammalia differ from the carnivorous more in the character of their 
large intestines than of their small intestines. The less putrefactive nature of their food 
renders it susceptible of a longer retention in the body ; and the receptacular and sac- 
cular character of the large intestines seems especially designed to retard the course of 
the alimentary substances. An observation made by the celebrated Surgeon Dupuytren, 
throws light upon the final purpose of this detention of the food of the Herbivora: he 
noticed in a patient who had an artificial anus near the end of the small intestines, 
that the vegetable parts of the food thence ejected were undigested. Dr. Beaumont 
also observed that the vegetable substances underwent much less change than the 
animal substances in the stomach of the man (Alexis) with the fistulous opening into 
the stomach. That organ in the artiodactyles (Peccari, Hippopotamus, and Ruminants) 
is rendered specially complex for overcoming the difficulty, and the cecum and colon 
are comparatively small: but in the perissodactyles (Horse, Tapir, Rhinoceros) the 
more simple stomach is compensated by the increased capacity and complexity of 
the large intestines. The subdivided stomach in the Sloths is in some respects, as 
e.g. the glandular appendage, and vascular secerning surface of the paunch, more com- 
plex than that of Ruminants: and here accordingly we find the czecum absent and the 
colon undefined. These facts should be kept in mind by the Physiologist when he draws 
from Comparative Anatomy in support of inferences as to the special function of the 
cecum in completing the digestion of vegetable food. The Dormouse and other hyber- 
nating Rodents are far from being the sole exceptions to the presence of a proportionally 
large czecum in the Herbivora: a large cecum is rather the exception than the rule in the 
vegetable feeders. It is only found in those Herbivora, in which, through the necessity 
of a correlation with other circumstances than that of the nature of the food, the stomach 
retains the simple form and moderate size of that of the carnivorous or mixed feeding 
mammals. Comparative Anatomy significantly warns us against ascribing a special or 
exclusive importance to any particular dilatation of the alimentary canal, It plainly 
demonstrates that neither a complex stomach nor a large cecum are essential to the 
digestion of vegetable food: but it teaches that a capacious and complex alimentary 
canal is essential for that purpose, at least in the Mammalia. Either a highly-deve- 
loped and concentrated glandular apparatus must be added to the stomach, as in the 
Dormouse, Wombat and Beaver ; or the stomach must be amplified, subdivided or sac- 
culated, as in the Ruminants and herbivorous Marsupials ; or both complexities must be 
combined, as in the Sloths, Dugongs and Manatees ; or, if asimple condition of stomach 
is retained, it must be compensated by a large sacculated colon and cecum. 
Digestive glands.—The liver presented the dark colour noticed by Mr. Thomas in his 
dissection of the Rhinoceros. In the female specimen which I examined, its texture 
was as firm as in the Horse, and its weight was 21 lbs. avoirdupois. In the older and 
