ODONTOGRAPHY. 67 



more than double the size of either of the two anterior four-pointed milk 

 molars, behind which it is situated. It is the tooth of a young animal, and 

 always has nearly the same size. It has, as before said, three ridges, 

 each of which is divided into two mastoid eminences. Surrounding the 

 base of the tooth, at its junction with the gum, is seen the prominent 

 ridge which encircles the whole tooth. The fangs were originally six in 

 number, but the two posterior are consolidated so as to form one. This 

 tooth measures, from before backwards, three inches ; transversely, two 

 inches ; height of the crown, an inch and a half ; circumference of the 

 neck, eight inches and a half; the anterior fang is two inches and six- 

 eighths in length, the posterior two inches. A drawing of this tooth is 

 given in Plate IX. Fig. 1 ; and its situation may be noticed in Plates II. 

 III. and V. 



The fowrth tooth in the order of development, being the next six- Fourth 



Tooth. 



pointed, and first permanent molar, is situated behind the last described, 

 and has the same form, but is much larger. The crown bears three trans- 

 verse ridges, each divided into two mastoid eminences ; the inner eminence 

 being notched. The base of the ridge is strongly marked at the anterior 

 and posterior extremities of the tooth. Between the ridges on the outer 

 >ide is a projecting tubercle not usually found. The fangs are two in 

 number ; an anterior, supporting the front ridge ; and a large posterior, 

 supporting the two remaining ridges. The measurements of this specimen 

 are from before backwards, three and a quarter inches ; transversely, two 

 inches and a half ; height of the crown, an inch and five-eighths ; circum- 

 ference of the neck, nine inches and a half. A drawing of this tooth is 

 given in Plate IX. Fig. 2, and its situation shown in Plates IV. V. 

 and VI. 



