514 PHILOSOPHICAL TRANSACTIONS. [ANNO 17QQ. 



by a strong enamel. There are from 4 to 8 of these points, joined together by 

 the common bony matter, which fills up the space between the enamelled portions. 

 When the grinder is farther advanced in the mouth, its foremost laminae are gra- 

 dually worn down by the mastication of the food; and these enamelled points or 

 denticuli disappear, one after another, till the enamel at last runs quite across the 

 tooth, surrounding the central part on which it was formed, and taking the irre- 

 gular indented plaited shape of the lamellae. This bony centre on which the 

 enamel is formed, is harder than the matter which joins the teeth together, does 

 not wear so fast, and consequently remains higher. 



The number of teeth of which a grinder is composed, varies from 4 to 23, ac- 

 cording as the elephant advances in years; so that a grinder or case of teeth, in 

 full grown elephants, is more than sufficient to fill one side of the mouth ; in pro- 

 portion however as the foremost layers are worn away, the succeeding ones come 

 forward, to supply their places. The denticuli of which each layer or tooth is 

 composed, are much larger, and fewer in number, in old than in young elephants; 

 in consequence of this, the same number of laminae generally fills the jaw of a 

 young or of an old elephant; and from 3 till 50 years, there are from 10 to 12 

 teeth or laminae in use, in each side of either jaw, for the mastication of the 

 food. When several of the anterior teeth of which a grinder is composed have 

 been completely formed, and each tooth covered with its proper enamel, they 

 become firmly united, beginning at the fore part, by the intervention of the 

 common bony matter, which gradually fills up the interstices between them. When 

 the bodies of several of the anterior laminae have been connected together the in- 

 ferior edge of each becomes united, in the same manner, to the one next it, till 

 the whole are thus gradually joined, and form a grinder or case of teeth. 



As soon as the anterior part of the grinder is thus firmly united, the fangs or 

 roots are next added: these at first appear in the form of a thin curtain or lamella 

 of bone, extending backwards, along some of the anterior laminae, at their lower 

 edges. A fang common to the 3 anterior teeth, first begins to be formed by the 

 ossification shooting across from each side, in a circular direction, at the anterior 

 portion of the first, and the posterior part of the 3d lamina. These join and 

 become longer, assuming a conical shape: the hollow is gradually filled up by suc- 

 cessive layers of the substance of the tooth, as the fang lengthens, till at last it 

 becomes solid. This however does not happen, till the 3 layers to which the fang 

 is attached are nearly worn away. When its ossification is almost completed, ano- 

 ther process begins to take place, which is, the absorption of the fang from its ex- 

 ternal surface. By the time that the anterior layers of the grinders are completely 



Elephantina, published in 1713, calls it dictations. The above work, which was put into my hands 

 by my friend Dr. Alex. Monro, jun., since this paper was written, contains some useful information. 

 The ingenious author had, in several particulars, a tolerable idea of the formation and structure of the 

 grinders j yet, far from suspecting a regular succession of them, he attempts to prove such succession to> 

 be impossible. He is equally erroneous in many other respects. — Orig. 



