ODONTOGRAPHY. 65 



across the tooth ; but the term ridge is more strictly applicable to the teeth 

 of Mastodon Giganteus, and that of lobe to the Mastodon Angustidens and 

 its varieties ; by mastoid, or mammillary eminence, a projection or division 

 of one of these ridges ; and by papillary eminence, a small pyramidal 

 intervening cone. All Mastodon teeth are also traversed by a longitudinal 

 furrow, separating the internal from the external mastoid eminences. 



M. Laurillard makes an observation, in regard to the teeth, which is 

 verified by our specimens with singular exactness. The first three teeth 

 are wider behind than in front, the two next square or parallelogramed ; 

 but the ultimate contracts gradually, so as to terminate in a blunt point. 

 The upper teeth are a little wider than the lower. 



Particular Description. — Eight anterior teeth, two on each side of each Particular 



Descrip- 



jaw, much smaller than the others, are developed soon after birth, shed at tion. 

 an early period, and have been called deciduous, or milk-teeth. Those of 

 the lower jaw are seen in perfection in the calf-jaw, as represented in Plate 

 II. Fig. 1. The anterior, or first of these, is of small size ; it has two bifid First 



Tooth. 



transverse ridges, slightly notched ; an anterior small sharp projection in 

 the centre of the front surface ; and a posterior, more distinct. The height 

 of the crown is seven-eighths of an inch ; the width across, also seven- 

 eighths ; from before backwards, an inch and a quarter ; circumference of 

 the neck, three inches and three-eighths. The fangs are two in number, 

 widely projecting, much curved, smooth anteriorly and posteriorly, but 

 hollowed in the interspace. The anterior fang, larger than the posterior, 

 is an inch and a half long by three-fourths of an inch wide ; the posterior 

 fang measures an inch and five-eighths in length, by nine-sixteenths of an 

 inch in width. The distance of the extreme tip of one fang from that of 

 the other is, on the outer side, five-eighths of an inch ; on the inner, three- 



9 



