230 
CORYPIIODON. 
animal in the type, since the last molar tooth, both above and below, is but 
just protruded. But their peculiar form cannot be traced to this fact, since 
the apical portions of the canines of other species difier utterly from the 
corresponding portions in the C.molestus. The last inferior molar resembles 
that of the G. siinus in having a strong cingular heel beiiind the posterior 
crest, and in lacking all tubercle or cingulum between the internal extremi¬ 
ties of the cross-crests. The general form of the crown is elongate, and 
the anterior descending crest is large, and extended Avell anteriorly to the 
inner side. The premaxillary bone is produced forward, so that the alveolus 
of the first incisor tooth is entirely in the horizontal portion, which is about 
0"’.02 longer than the vertical portion to its extremity in contact with the 
nasal bone. 
The cranium of the typical individual presents the strong supratem- 
poral crests already described in the C. ele])hantopus. They extend from 
behind the orbits, and are produced so as to extend far behind the vertical 
plane of the occipital condyles, uniting in a deep notch on the middle line 
of the superior surface. Thus the supraoccipital region is deeply concave. 
Tlie mastoid processes are stout, descending to a little below the line of the 
inferior borders of the occipital condyles. Tiiey present a deep fossa on 
the superior part of the external side, whicli doubtless marks the sutural 
separation of the paramastoid from the mastoid portions. The latter is con¬ 
tinuous above with the prominent inferior border of the temporal fossa, 
which overarches the meatus auditorius externus. No tuberosities nor horn- 
cores appear on the superior surface of the skull. The superficial layer 
of bone on the posterior half has a fine reticulate rugosity. The nasal 
bones are narrow anteriorly, and their free distal portion is narrow, short, 
and rathei’ stout, and acuminate in outline. They do not extend so far 
forward as the anterior margin of the palatal portion 'of the premaxillary 
bones, but reach about to the line of the point of the posterior divergence 
as defining the inferior border of the external nares. They are well dis¬ 
tinguished by persistent su'ture. The ascending joortions of the premaxillary 
bones are nearly vertical, and are narrow. The horizontal portions do not 
appear to be suturally united on the median line, but are in close contact. 
A view of the skull from below shows that the condyloid surfaces are 
