308 
PEOBOSCIDEA. 
indicate the borders of three crests. The last or sixth molar is just pro¬ 
truded, and the anterior two crests are the only ones worn. It was frac¬ 
tured in transportation, so that the anterior and posterior heels are incom¬ 
plete; but a sketch, which I made from it when perfect, and before I 
removed it from the matrix, supplies this deficiency. The crown in its 
perfect state presented four transverse crests, a strong heel, and a small 
anterior cingulum. The crests are constituted of two principal obtusely 
conic tubercles, separated by a deep fissure. Those of the external series 
are attended by others, and those of the inner side are more simple. The 
last of the inner row is entirely simple; the penultimate has a trace of 
division at its apex. The second has a decided fissure, separating a lower 
division next to the median line, which is more strongly developed in the 
first. At the base of the second in front is a low tubercle, which corre¬ 
sponds to the cingulum in front of the first. The external cones present 
two accessory tubercles in front and one behind; the inner one of the 
former is wedged between the principal cones, while the more anterior one 
is in contact with the posterior one of the preceding series, thus completely 
dividing the transverse valleys into two unequal parts. The posterior 
tubercle is the largest, and has a convex posterior border, which is divided 
into three or four lobes by transverse grooves, forming a step-like outline in 
profile, all of which disappears on attrition. The principal lobes are ojrpo- 
site to each other, and the transverse series are convex forward. The 
enamel, even in the young tooth, is nearly smooth, and the basal cingulum 
very little marked. 
Measurements of the mandible. 
M. 
Total length from the apex of the tusks to the posterior border of the molar.. 
Length of the superior oblique border of the spout. 
Length of the symjihysis without the tusks. . 
Length of the exposed part of the tusks... 
Diameter of the same at the base 
i transverse 
\ vertical... 
0. 7o() 
0. 240 
0. 200 
0.100 
0. 040 
0. 032 
Width of the spout at the base. ... 0.110 
Width of the same between tlie superior ridges. . 0. 040 
Length from the symphysis to the base of the fifth molar tooth. 0.100 
Depth of the ramus at the fifth molar. 0.127 
Depth of the ramus at the sixth molar. 0.118 
Diameter of the ramus at the same point. 0.150 
