74 



mil mode of growth. They do not extend so far back within the jaw as in 

 most rodents, and in this respect are more like those in the rabbits, or, as in 

 their nearer relatives, the peccary and hog. They extend beneath the pre- 

 molars, but the bottom of the alveolus does not reach the position of the first 

 molar. 



The incisors are convex in front, and not flat, as usual in rodents. The 

 anterior convexity is invested with thick enamel longitudinally striated, the 

 striae being wrinkled. Externally the edge of the enamel appears proportion- 

 ately more prominent than in rodents ; that is to say, it projects more above 

 the level of the contiguous exposed dentine. In transverse section the incisors 

 are ovoid, with the narrow extremity behind. The fore and aft diameter of 

 the section is 10 lines ; the transverse diameter at the edges of the enamel 

 layer is 6£ lines. The anterior convexity covered with enamel is 4 lines ; 

 the posterior convexity is £ an inch. 



The cutting edges of the incisors are broken, but the extremities of the 

 teeth are sufficiently well preserved to exhibit the manner of wearing. They 

 were not only worn in a sloping manner backward, as in rodents, but also 

 externally, so that it appears the upper incisors were more divergent than the 

 lower ones, and held a position related .to them more like the condition 

 observed in the peccary. 



The rami of the jaw, as usual in pachyderms, are completely co-ossified. 

 The symphysis is remarkably strong and deep, and in the median line is 

 nearly 3 inches in length. The rami just back of the symphysis are nearly 

 an inch thick. The chin forms a long, broad slope, defined at the sides by 

 the prominences of the large incisor alveoli, curving from the base of the 

 jaw parallel with each other upward and forward. The chin resembles that 

 of the peccary or rhinoceros, but is more convergent, as in the beaver. 

 Approaching the exit of the large incisors from their alveoli the intermediate 

 space is deeply grooved, as represented in Fig. 3. 



The body of the ramus is short, deep, and thick. Its outer surface is ver- 

 tical^ convex. The base is thick and convex fore and aft as well as trans- 

 versely. 



The masseteric fossa is deep, and extends downward to about the middle 

 line of the body of the ramus. Two mental foramina on one side, and three 

 on the other, occupy a position in advance of that of the last premolar. 



