63 THE HORSE. 



Verlehraltd animals are those whicli have a cranium, or bony cavity, 

 containing the bruin, and a succession of bones, called the spine, and the 

 divisions of it, verLebrce., proceeding from the cranium, and containing a 

 prolongation of the brain, denominated the spinal marrow. 



Invert ehraled animals are those which have no vertebrae. 



The horse then belongs to the division vcrtebrated, because he has a era- 

 nium or skull, and a spine or range of vertebrae proceeding from it. 



Tlie vertebrated animals, however, are very numerous. They include 

 man, quadrupeds of all kinds, birds, fishes, and many reptiles. We look 

 out then for some subdivision, and a very simple line of distinction is soon 

 presented. Some of these vertebrated animals have mammce, or teats, 

 with which the females suckle their young. The human female has 

 two, the mare has two, the cow four, the bitch ten or twelve, and the sow 

 more than twelve. 



This class of vertebrated animals, having mammae or teats, is called 

 mammalia, and the horse belongs to the division vertebrata, and the class 

 mammalia. 



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

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

 that " this class of quadrupeds, or mammiferous quadrupeds, admits of a 

 division into two Tribes. 



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

 cally called unguiculata, from the Latin word for nail; and 



II. Those whose 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 ungulaia, or hoofed. 



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 im- 

 mediately received into the stomach and digested ; but in othei's, the food, 

 previous to digestion, undergoes a very singular process. It is returned 

 to the mouth, to be re-masticated 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, to be chewed 

 again. 



The ungulata that do not ruminate are somewhat improperly called 

 pachydcrmata, from the thickness of their skins. The horse does not ru- 

 minate, and therefore belongs to the order jpachydermala. 



The pachydcrmata who have only one toe belong to the family solipcda 

 — singk footed. Therefore the horse ranks under the division vertebrata ; 

 — the class mammalia; — the tribe ungulata; — the order pachydcrmata; — 

 and the family solipeda. 



The solipeda consists of several s'pecies, 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 tusk. 



