96 
CREODONTA. 
the genus Hymnodon than to any other of later age. It differs from both 
the genera named in having only six molar teeth, and the triangular type of 
inferior sectorial teeth is not seen in either. 
On a former occasion, I wrote the dental formula of Oxyana, molars 
3-3 (Annual Report of the Chief of Engineers, 1874, p. 599), but now 
transfer one tooth from the premolar to the molar series, in accordance with 
the correct homology, so as the read 4-2. 
The exterior portion of the posterior transverse superior molar is a 
transverse blade, interior to which is one or probably two subtriangular 
cusps. The blade shuts down in contact with the plane, posterior face of 
the united middle cusps of the last inferior molar, and the cusp shuts down 
on the. inner side of the heel of the same where the surface is often seen to 
be worn obliquely by it. The elevated cusjds of the last inferior molar 
close into a deep fossa of the maxillary bone; the blades of the external and 
anterior cusps shearing against the inner side of the posterior median cusp 
and posterior blade of the penultimate superior molar. The inner heel of 
the latter opposes transversely the posterior heel of the penultimate inferior 
molar, shearing somewhat with the posterior border of the united median 
cusps. The external and anterior cusps of the penultimate inferior molar, 
with their external sliear, fit within the median cus^o and posterior blade 
of the antepenultimate superior molar, and are received into a correspond¬ 
ing pit of the maxillary bone, Avhich is not so deep as the posterior fossa. 
The surface of the maxillary between this tooth and the last premolar is 
only slightly concave. Thus, in this genus, and the arrangement is similar 
in Stypolophiis, each inferior tubercular sectorial tooth makes two shears with 
two corresponding superior molars, viz, a posterior transverse with the 
superior molar behind it, and an external oblique with the superior molar 
corresponding to it. This does not occur in any recent Carnivora^ and is a 
more complex, although much less powerful, arrangement than they possess. 
The skull in this genus is robust. In the O.forcipata^ there is an elevated 
sagittal crest, and the superior walls of the cranium are. massive. The 
crest divides on the posterior part of the frontal region, and disappears. 
The zygomata are short and deep, and laterally expanded. The malar 
