ARTIODACTYLA. 
353 
displays a long diastema, and, like all other specimens of the genus yet 
obtained, does not exhibit the teeth anterior to it, but a portion of an alveo¬ 
lus only. There is a single small mental foramen immediately below the 
anterior root of the second premolar. 
The molars differ from the premolars in not being prismatic in form; 
their crowns are contracted at the base fore and aft, and distinguished from 
the roots. They are slightly convex on the external side, but present strong 
vertical crests on the inner side. The third and fourth premolars present 
three of these, of which the anterior is the incurved anterior margin, but 
the posterior is a branch. The molars are much compressed, especially the 
last. The inner crescents rise in acute points; the external wear flat. There 
are no tubercles between the bases of the external columns. The enamel 
is finely and obsoletely roughened. 
Measurements. 
M. 
Length of the molar series...... 0. 0565 
Length of the diastema..... 0.0275 
Depth at the last molar. 0. 0210 
Depth at the second (first) preraolar..... 0.0120 
Depth of the diastema at the middle... . 0. 0070 
Length of the premolars... 0. 0210 
Length of the first true molar.... 0. 0000 
Width of the first true molar.... 0. 0050 
Portions of a second individual display similar proportions. 
The mandibles of the JDicrocerus furcatus are about the size of those of 
a Sheep. 
Dicrocerus necatus, Leidy. 
Plates Ixsxi, figs. 2-6; Ixxxii, figs. 2-3. 
Merycodiis necatus, Leidy, Proc. Acad. Phila., 1854, pp. 90-157; 1857, p. 89; 1858, p. 
23; Jour. Acad. Phila., vii, p. 162, pi. xiv, figs. 9-10. 
Cervus icarrenii, Leidy, Proc. Acad. Phila., 1858, p. 23; Jour. Acad. Phila., vii, 1869, 
p. 172, pi. xxvii, fig. 12. 
Dicrocerus necatus, Cope, Proc. Acad. Phila., 1875, p. 257. 
This species is represented by the horns of seven individuals, two of 
which present those of both sides. Each of these individuals includes also 
the inferior dentition, and one of them a part of the maxillary bone, with 
its teeth. The identification of the mandibular rami and dental characters 
23 G B 
