PETERSON : NEW CARNIVORES FROM MIOCENE OF WESTERN NEBRASKA 209 
heavier ridge on the antero-internal angle of the paroccipital process, thus separating 
the large pit for the tympanohyal externally, the jugular foramen, and the foramen 
lacerum posterius internally. The bulla seems to be fairly well fused to the tym- 
panic region while in the Oligocene genus it apparently always slipped off. From 
a study of the tympanic bulla in Daphenodon superbus it is quite evident that though 
quite solidly attached along the antero-external angle and along the border of the 
basioccipital, the bone is not nearly so well ankylosed by the paroccipital process 
and the mastoid as for instance in Canis. In Daphenus felinus the bulla appears 
to be more loosely attached to these processes than in the type under description. 
This fact apparently supports Mr. Hatcher's contention that the ankylosed auditory 
bulla in recent dogs should be regarded as a specialized character.’ 
It is interesting to note that the tympanic bulla in Cynodesmus brachypus (Cope) 
is, in the first place, larger; and, secondly, much better ankylosed with the sur- 
rounding bones than in the form under description, and more nearly approaches 
that of Canis. Professor Cope* and Dr. Matthew‘ have observed that the paroccipi- 
tal process in Cynodesmus brachypus projects ‘‘ backwards nearly as far as the pos- 
terior face of the occipital condyles.” After a careful study of this region in the 
type of Cynodesmus brachypus, now before me, it would seem that the backward pro- 
jection of the paroccipital process, regarded as a primitive character by Matthew, is in 
reality due very largely to crushing, there being no part of the base of the skull 
which is left undisturbed. Besides, if the present position of the paroccipital process 
of the skull of C. brachypus is a natural one it would interfere with the free move- 
ment of the occipital condyle upon the atlas. Unfortunately the paroccipital proc- 
ess of the left side of C. brachypus has been broken off, which otherwise might have 
furnished good verification. From Dr. Matthew’s statement and illustrations (J. ¢.) 
it is very evident that the paroccipital process in Cynodesmus thomsoni is closely 
connected to the tympanic bulla and _ points almost directly downward at the tip, 
while in Cynodesmus thodides Scott’ the process is heavy and projects thore back- 
ward. It is quite likely that in a more perfect specimen of C. brachypus the condi- 
tion of the paroccipital process would be found to be more like that in C. thomsona 
and certainly not more backwardly directed than in C. thodides. The postglenoid 
process of ©. brachypus has proportionally a less transverse diameter than in 
Daphandon superbus and is more nearly similar to that of Canis, while the foramen 
opticum occupies a similar position, 7. ¢., more in advance of the exit of the foramen 
rotundum than in recent dogs. 
4“ Oligocene Canidi, "MEMOIRS CARNEGIE MusEuM, Vol. I, pp. 72-73, 1902. 
5 Bull. U. §. Geological and Geographical Survey of the Territories, Vol. VI, p. 389, 1881. 
‘Bull. Am. Mus. Nat. History, Vol. XXIII, p. 186, 1907. 
‘Trans. Am. Philos. Society, Vol. XVII, p. 66, Pl. I, fig. 1893. 
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