5S8 MANUAL OF ZOOLOGY. 



Lower Tertiary Rocks. The Anoplotheria were slender in 

 form, with long tails, and feet terminated by two hoofed toes 

 each, sometimes with small accessory hoofs. The dentition 

 consisted of six incisors in each jaw, small canines not larger 

 than the incisors, and seven molars on each side, there being 

 no interval or diastema between the molars and the canines. 



RUMINANTIA. 



The last section of the Artiodadyle Ungulates is the great 

 and natural group of the Ruminantia, or Ruminant animals. 

 This section comprises the Oxen, Sheep, Antelopes, Giraffes, 

 Deer, Camels, &c., and is distinguished by the following char- 

 acters : — 



The foot is what is called "cloven," consisting of a symmet- 

 rical pair of toes encased in hoofs, and looking as if produced 

 by the splitting into two equal parts of a single hoof. In addi- 

 tion to these functional toes, there are sometimes two smaller 

 supplementary hoofs, placed at the back of the foot. The 

 metacarpal bones of the two functional toes of the fore-limb, 

 and the metatarsal bones of the same toes of the hind-limb, 

 coalesce to form a single bone, known as the " canon-bone." 

 The stomach is complex, and is divided into several compart- 

 ments, this being in accordance with their mode of eating. 

 They all, namely, ruminate or " chew the cud " — that is to say, 

 they first swallow their food in an unmasticated or partially- 

 masticated condition, and then bring it up again, after a longer 

 or shorter time, in order to chew it thoroughly. 



This process of rumination is so characteristic of this group, 

 that it will be necessary to describe the structure of the 

 stomach, as showing the mechanism by which this singular 

 process is effected. The stomach (fig. 217) is divided into 

 four compartments, which are usually so distinct from one 

 another that they have generally been spoken of as so many 

 separate stomachs. The gullet opens at a point situated 

 between the first and second of these cavities or "stomachs." 

 Of these the largest lies on the left side, and is called the 

 "rumen" or "paunch" (fig. 217, r). This is a cavity of very 

 large capacity, having its interior furnished with numerous 

 hard papillse or warts. It is the chamber into which the food 

 is first received when it is swallowed, and here it is moistened 

 and allowed to soak for some time. The second stomach, 

 placed to the right of the paunch, is much smaller, and is 

 known as the "reticulum" or "honeycomb-bag" {h). Its 

 inner surface is reticulated, or is divided by ridges into a 



