322 THE ANATOMY OF VERTEBRATED ANIMALS. 



complete, and both upper and lower molars put on the Rumi- 

 nant characteristics. In dentition, Gainotherhim differs from 

 a Ruminant only in possessing all the upper incisors, while 

 no existing adult Ruminant has more than the outer upper 

 incisors. We are of course unacquainted with the structure 

 of the stomach in these animals, but they so closely resemble 

 Ruminant AHiodactyla that it is highly probable they may 

 have possessed the faculty of rumination in a more or less per- 

 fect degree. 



B. The Huminantia. — In the commonly-recognized mem- 

 bers of this division of the Artiodactyla there is never more 

 than one pair of incisors, and that the outermost, in the upper 

 jaw of the adult. Canines may or may not exist in the upper 

 jaw ; they are always present in the lower jaw, and are gen- 

 erally inclined forward and closely approximated to the inci- 

 sors, which they usually resemble in form. It consequently 

 happens that they are often reckoned as incisors, and Rumi- 

 aants are said to possess eight cutting teeth in the lower jaw. 



With one exception [Ryoeinosckus), the metacarpal and 

 metatarsal bones of the third and fourth digits early become 

 anchylosed together into a single, so-called cannon-bone. 

 There is a peculiar bone called malleolar^ which takes the 

 place of the distal end of the fibula, articulating below with 

 the calcaneum and above with the astragalus. 



The great majority of the Ruminantia possess horns, the 

 bony supports, or cores, of which are developed on each side 

 of the middle line ; and, except in the Giraffe, are outgrowths 

 of the frontal bones. 



The stomach has, at fewest, three divisions ; and, in the 

 majority of the Ruminantia, it has four compartments. 



If the stomach of a typical Ruminant, such as a Sheep or 

 an Ox, be examined, it will be found to be divisible into two 

 principal moieties, the one cardiac and the other pyloric, while 

 each of these is again subdivided into two others. Thus the 

 extreme cardiac end of the cardiac moiety is dilated into an 

 enormous sac of irregular form, the mucous membrane of 

 which is raised up into a vast number of close-set papillfe. 

 This chamber is the Rumen, or Paunch. It communicates, 

 by a wide aperture, with a much smaller chamber, which coi> 

 stitutes the second subdivision of the cardiac moiety. This is 

 called the Reticulum, or JSbneycomb stomach, from the fact 

 that its mucous membrane is raised up into a great number of 

 folds, which cross one another at right angles, and, in this 

 way, enclose a multitude of hexagonal-sided cells. The reticu- 



