»3J THE HORSE. 



Verfehrated animals are tliose which have a cranium, or bony cavity, 

 containing the brain, and a succession of bones, called tlie spine, and the 

 divisions of it, verlcbrce, proceeding from the cranium, and containing a 

 prolongation of the brain, denominated the spinal marrow. 



Invertebrated animals are those wliich have no vertebrae. 



The horse then belongs to the division vertebrated, because he has a cra- 

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



The 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 mamma 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 veriebrata, and the clas.T 

 mammalia. 



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

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

 that " this class of quadrupeds, or mammiferous quadrupeds, adi uts of a 

 division into two Tribes. 



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

 cally called ungiiiculata, 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 ungulata, 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 others, 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 

 ruminanlia, or ruminants, from the food being retwned, from one of th*^ 

 stomachs (for they have four), called the rumen or paunch, to be chewe*' 

 again. 



The 7mgulata that do not ruminate are somewhat improperly calle^-' 

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

 minate, and therefore belongs to the order pachydermata. 



The pachydermata who have only one toe belong to the family solipedi 

 — 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 consists of several species, as the horse, the ass, the mule, 

 and the quagga. 



First stands the Equus Caballtjs, 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. 



