68 OSTEOLO(iY OF THE HORSE. 



hard, solid bone, which is organic ; and a still whiter and harder 

 part, called enamel^ which is inorganic. It is only the body of 

 the tooth which is coated with enamel; the root is quite destitute 

 of it: the former owes its polished whiteness to it. Upon the face 

 it is variously disposed, according to the form of the tooth, from 

 which it sinks, more or less deeply, into the heart of all teeth 

 excepting the tusks; forming thereby small funnel-shaped ena- 

 mellated cavities, called the infundibula, whose mouths, named 

 ihe pits, are indicated by the black marks upon the faces. 



The tooth is essentially formed of bone, the enamel being no 

 more than a covering or defence to it. Within the bone is a 

 cavity, corresponding in shape and dimensions to the tooth itself. 

 This, the cavitjj of the tooth, contains the pulp, inclosed within 

 the membrane of the tooth: these parts are amply furnished with 

 blood-vessels and nerves, which gain admission through the points 

 the fangs. 



Distribution. — Into three classes: 1st, the Incisors, or cutting 

 teeth ; 2d, the Molares, or grinding teeth ; 3d, the Canini, or tusks. 



The incisors, twelve in number, are ranged in parabolic 

 curves in the anteriormost parts of the jaws. — Form — A bent 

 cone, of which the face is the basis; the fang, the apex. Face, 

 elliptical. Pit of the same figure, and single. Fang, single, 

 conical. The teeth in the upper jaw are somewhat larger than 

 those in the lower. The forms, but more particularly the faces, 

 of these teeth undergo alteration as age advances. 



Thk molars, twenty-four in number, are implanted, in four 

 rows, into the sides of the jaws — twelve in the upper, and twelve 

 in the lower maxilla, six on each side ; equal in magnitude to 

 four or five incisors united together.' — Figure, oblong, quadrangu- 

 lar, excepting the first and last, which are triangular. , Fucen, pre- 

 senting two transverse ridges and two pits : those of the triangular 

 teeth have an additional eminence. Infundibula, two in each 

 tooth, which imperfectly divide the cavity, by extending through 

 it down to the fangs, into chambers. — Fangs: an upper molar 

 possesses three, excepting the first and last teeth, which have, 

 occasionally, but two each. The lower molars have but two fangs. 



The canine teeth, or tusks, are four in number, two in 

 each jaw, having isolated stations in the interspaces at the sides 

 of the body of the maxilla, between the lateral incisors and the 

 first molars. — Form, a double cone, slightly incurvated, whose 

 bases are joined together in one body : during growth the inner 

 side is slightly concave and fluted. — Cai'/Yj/ extends uninterrupt- 

 edly through the whole length of the tooth. — Fang, single and 

 perforated. No infundibulum. — Characteristic of the male : in 

 the female, either imperfect or undeveloped. 



