PETERSON : NEW CARNIVORES FROM MIOCENE OF WESTERN NEBRASKA 259 
it is quite safe to say that this individual did not possess this character of the verte- 
bree. Another important feature is seen in the prominent antero-posterior ridge in 
the floor of the neural canal, which is pierced by a transverse venous foramen, while 
in the type specimen this ridge is rather poorly developed and the area in the middle 
region, where the foramen is located in the larger specimen, is much greater and 
was not always bounded above by a bony bridge so as to forma foramen. ‘The 
transverse process is proportionally much shorter, which would indicate a narrower 
neck in the larger individual. 
In the Amherst specimen, which is about equal in size to the one represented 
by the cervical vertebree described above, there are some lumbar vertebrae preserved. 
One of these has the transverse processes preserved. ‘These processes are propor- 
tionally longer than those in the corresponding region of the lumbars in the type, 
and more in accordance with the conditions found in Daphenus, Temnocyon, and 
the recent forms. The os penis of the Amherst specimen of Daphenodon is greatly 
different from that in No. 1589a (Carn. Mus. Cat. Vert. Foss.) and is described on 
pages 230 and 231. 
Rexatrionsuies oF Daphanodon. 
That Daphenodon had its true ancestor in Daphenus of the Oligocene forma- 
tion can hardly be doubted, from the study which has resulted in the above com- 
parative description. Daphenus in turn is generally regarded as a descendant of 
the Miacide of the earlier Tertiary of North America. In the Oligocene and early 
Miocene there were a number of diverging lines, which as a whole were neverthe- 
less quite homogeneous in their general structure, though apparently sufficiently 
diversified to show with more or less clearness their destiny in later times. These 
points have already been ably treated by Scott, Boule, Schlosser, Matthew, Merriam, 
Hatcher, Wortman, and others, and will not be discussed in the present paper, except 
in so far as to assign the phyletic position of Daphenodon. 
It would appear that Daphanodon is not yet represented by any very closely 
allied species” in the intervening formations from the lower Harrison beds down to 
the lower portion of the Oligocene where Daphenus, its predecessor, is found. The 
genera from the John Day are already too far advanced in different ways to be 
seriously considered as intermediate forms. Thus Zemnocyon and Mesocyon have m* 
absent and differ in many other important respects, some species” of the latter genus 
having a well developed entoconid on the lower sectorial, and being possibly 
2 Mesocyon robustus Matthew from the lower Miocene of South Dakota bears general similarities, but m, is 
apparently too much reduced and more trenchant, and m; is probably sometimes absent. 
2 Mesocyon Josephi (?). See Merriam, Univ. of Cal. Publications, Bull. Dept. Geol., Vol. V, pp. 19-20, 1906. 
