].")() The American Geologist. March, 1894 
The principal specific characters are: Post-tympanic and 
post-glenoid processes confluent throughout two-thirds their 
length, entirely enclosing the external auditory meatus. Ptery- 
goids slightly bifid. Anterior border of posterior nares on a 
line with posterior border of median sinus of second molar. 
Nasals not eo-ossified. The structure of the teeth is very 
much obliterated by the wear to which they were subjected 
before the animal died. The inferior and superior molars are 
all represented in the type specimen, as well as the fourth 
upper and lower premolars. Of the superior dentition the 
second and third molars are the least worn, and, therefore, 
present the most trustworthy characters. The dorsum is very 
Hat. The median costa is entirely wanting, and the anterior 
and posterior costa are but weakly developed. The anterior 
sinus is (piite small and the anterior vallum is not strong. The 
median sinus is well developed and obstructed by a very large 
anticrochet and a small crista, but there is no crochet, as lie- 
fore stated. The posterior sinus is of ordinary size with a 
strong posterior vallum. In the last upper molar only there is 
a distinct median tubercle. In the type specimen the first 
upper molar and fourth premolar are BO much worn that the 
enamel at the bottom of the median sinus, between the base 
of the anticrochet and the opposite side, has been removed, 
thus cutting off the inner portion of the median sinus, which 
now appears as an anterior fossette. By the same wear the 
enamel once covering the posterior vallum has been entirely 
removed in these teeth, and as a result the posterior sinus 
now appears as a posterior fossette. The anterior borders of 
the upper molars and premolars are convex, the posterior bor- 
ders concave, excepting that of the last molar, which is con- 
vex. The molar and premolar teeth are very large in compar- 
ison with the skull, and the maxillaries are proportionately 
Strengthened in order to receive them. The inferior molars 
and premolars seem t<> present no distinctive characters. 
To the kindness of Prof. YV . B.Scott, who had charge of the 
expedition. I am indebted for the privilege of publishing this 
preliminary notice, which will be followed later by a full de- 
scription, with figures, of this and other material from the 
same becb. 
