180 MEMOIRS OF THE CARNEGIE MUSEUM 
THE Superior DENTITION. 
Unfortunately, only the incisors are present in the skull. The grinders have 
all dropped out. The specimen is injured in the posterior part of the alveolar border 
and the region of the pterygoids. ‘The superior incisors are nearly as strong relatively, 
as they are in Steneofiber fossor, and are of practically the same pattern: a nearly flat 
anterior surface, with heavy enamel. ‘The gnawing surface is gradually worn down 
to a broad, thin, chisel-shaped point. 
There are only two alveoli (for p*, m+) preserved on the left side of the maxil- 
lary ; the anterior one (p*) is smaller than the succeeding one, and does not appear 
— judging from its size—to have been occupied by a large tooth, such as is found 
in Steneofiber. On the right side, there is no alveole for p+, and on excavating this 
side of the maxilla, there was found no evidence of the presence of this tooth. This 
may be an accidental character of this particular individual, and may have no 
specific value. 
oe Tue Inrertor DeEntiTIon. 
The inferior incisors are both broken off close to the roots, and there are three 
grinders in the left ramus. In cross-section, the incisors are subtriangular, similar to 
the upper incisors, with a broad, smooth, heavily enameled anterior face. 
The premolar (pz) has very nearly twice the antero-posterior diameter of the 
succeeding tooth, which is contrary to what appears to have been the case with the 
corresponding teeth of the upper jaw, judging from the alveolus. The width of py 
slightly exceeds that of the succeeding two molars. ‘There are three irregularly 
placed enamel lakes on the grinding surface of pg; two of them antero-internal and 
transverse, the third oblique and postero-external. On the postero-internal enamel 
border there is a minute groove. This groove may be the remnant of the third 
internal enamel fold, asin Steneofiber. There isa slight evidence of the third enamel 
lake as in the latter genus, but in /. platyceps its greatest diameter is antero- 
posterior and it is not transversely placed. 
The diameter of the first molar is one third greater transversely than antero- 
posteriorly. It has two enamel fossettes ; the anterior one is transverse, and appears 
to be the only remaining evidence of the internal enamel folding, the posterior one 
is curved and oblique, similar to that.on pg. The second molar is similar to the 
first in every detail. There is apparently no alveolus for mg, and it is question- 
able if there was one. ‘The root of the incisor is very close to the alveolar border in 
this region, so that, if the third molar had been present at any time, it must have 
been small, and must have had a weak support. The teeth have roots similar to 
those in the genus Stencofiber. 
