5.1 8 MANUAL OF ZOOLOGY. 



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

 Deer, Camels, &a, 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 usually two smaller sup- 

 plementary hoofs placed at the back of the foot. The meta- 

 carpal 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 compartments, 

 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. 199) 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. 199, r.) This is a cavity of very 

 large capacity, having its interior furnished with numerous 

 hard papillae 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 

 number of hexagonal or many-sided cells, somewhat resem- 

 bling the cells of a honeycomb. The reticulum is small and 

 globular, and it receives the food after it has lain a sufficient 

 time in the paunch. The function of the reticulum is to com- 

 press the partially-masticated food into little balls or pellets, 

 which are then returned to the mouth by a reversed action of 

 the muscles of the oesophagus. After having been thoroughly 

 chewed and prepared for digestion, the food is swallowed for 

 the second time. On this occasion, however, the triturated 

 food passes on into the third cavity (/), which is variously 

 known as the "psalterium," "omasum," or (Scottice) the "many- 



