THE ZOOLOGICAL CLASSIFICATION OF THE HORSE. 107 



The class mammalia is still exceedingly large, and we must again subdivide 

 it. It is stated (Library of Entertaining Knowledge, vol. i. p. 13) that " thisi 

 class of quadrupeds, or mammiferous quadrupeds, admits of a division into two 

 Tribes. 



" I. Those whose extremities are divided into fingers or toes, scientifically 

 called unguiculata, from the Latin word for nail; and II. Those whoso 

 extremities are hoofed, scientifically called ungulata, from the Latin word for 

 hoof. 



" The extremities of the first are armed with claws or nails, which enable 

 them to grasp, to climb, or to burrow. The extremities of the second tribe are 

 employed merely to support and move the body." 



The extremities of the horse are covered with a hoof by which the body is 

 supported, and with which he cannot grasp anything, and therefore he belongs 

 to the tribe ungulata or hoofed. m 



But there is a great variety of hoofed animals. The elephant, the rhinoceros, 

 the hippopotamus, the swine, the horse, the sheep, the deer, and many others, 

 are ungulated or hoofed ; they admit, however, of an easy division. Some of 

 them masticate, or chew their food, and it is immediately received into the 

 stomach and digested ; but in others the food, previous to digestion, undergoes 

 a very singular process. It is returned to the mouth to be remasticated, or 

 chewed again. These are called ruminantia, or ruminants, from the food being 

 returned from one of the stomachs (for they have four), called the rumen or 

 paunch, for the purpose of remastication. 



The ungulata that do not ruminate are, somewhat improperly, called pachy- 

 dermata, from the thickness of their skins. The horse does not ruminate, and 

 therefore belongs to the order pachydermata. 



The pachydermata who have only one toe belong to the family solipeda — 

 single-footed. Therefore the horse ranks under the division vertebrata — the 

 class mammalia — the tribe ungulata — the order pachydermata — and the family 



solipeda. 



The solipeda consist of several species, as the horse, the ass, the mule, and 



the quagga. 



First stands the Equus Caballus, or Common Horse. 



Animals are likewise distinguished according to the number, description, and 

 situation of their teeth. The horse has six incisors or cutting teeth in the 

 front of each jaw ; and one canine tooth or tush. 



On each side, above and below — at some distance from the incisors, ana 

 behind the canines, and with some intervening space— are six molar teeth, or 

 grinders; and these molar teeth have flat crowns, with ridges of enamel, and 

 that enamel penetrating into the substance of the tooth. 



The whole is thus represented by natural historians:— 



Horse—Incisors 1 , canines 1=1, molar *=±. Total, forty teeth. 

 6 1 — 1 o— o 



To this short chapter we may properly append The Skeleton of tb* 



Horse. 



