T^.NTODOT?TA. 
1(51 
which presents to the other apex, has a wide longitudinal groove. The 
inferior enamel hand covers a prominent rib, which, near the apex, projects 
so as to be 0.66 of a cylinder; its enamel is not grooved, but has, like that 
of the superior band, an obsolete trace of wrinkling. 
The large inferior incisors are beveled on their posterior edge far 
below the apex, so that the outlines of the teeth are not parallel, as in the 
species of Calamodon. In the similar incisors of the second size, the 
posterior bevel is much shorter and more abrupt, and the posterior border 
of the shaft is not quite concentric with the anterior, converging a little 
toward the apex. In the smallest teeth of this type, the two borders are 
nearly parallel. The section of the two larger kinds of teeth is diamond- 
shaped; that of the smallest, a narrow oval. The enamel band on the two 
larger kinds of teeth is quite protuberant, but in the least it is narrow and 
merely convex. The enamel band on the largest inferior incisors is slightly 
convex on one side; and, on the other side, where it is more extended back¬ 
ward, it exhibits a shallow longitudinal concavity. Both sides are obsoletely, 
but distinctly, longitudinally ribbed. The enamel of the teeth of the medium 
size is quite similar. The dentinal shaft of the largest is contracted to a 
narrow edge behind; that of the second size is more obtuse. 
The enamel of all the molars is smooth, and without cingula. The 
transverse crests of the unworn true molars support two tubercles, and the 
inner extremities of the crests of the premolars are produced in accordance 
with the oblique wearing of the incurved crown in mastication. 
Measurements. 
Length of the inferior incisor, largest. 
Width of the same. 
Depth of the same.. 
Length of the incisor, medium, type 1. 
Width of the same . 
Depth of the same... 
Depth of the incisor, least, type 1.. 
Width of the same. 
Length of the superior incisor. 
Width of the same... 
Diameter of the crown of a premolar^ longitudinal 
) transverse .. 
M. 
0. 043 
0. 013 
0.018 
0.034 
0. 006 
0. 014 
0. 009 
0. 004 
0. 031 
0. 021 
0.010 
0.010 
11 G R 
