12 



University of California Publications. 



[Geology 



basin-shaped talon, and by the absence or weak development of 

 the external eingulum, excepting a faint ridge below the para- 

 conid. The hypoconid and entoconid are sharply compressed 

 ridges connected posteriorly, while in the form represented by 

 No. 10256 the entoconid is smaller, is nearly conical and is not so 

 closely connected with the hypoconid. On M 2 there is a small 

 but acute paraconid. Although smaller than the other tubercles 

 of the trigonid, it is nevertheless distinctly developed. The en- 

 amel of most of the premolars and molars is strongly wrinkled. 



It seems not improbable that the lower jaws referred to Ga- 

 lecynus lemur by Cope really belonged in C. (?) oregonensis. 

 None of the specimens described by him were in association with 

 crania. The dimensions of his specimens are almost identical 

 with those of oregonensis. As indicated elsewhere, 5 there is some 

 reason to believe that a number of the very small inferior sec- 

 torials showing the peculiar characters of latielens really repre- 

 sent lemur. 



MEASUREMENTS. 



No. No. No. 



"3T6" Ifo TTST 



Length of mandible, anterior side canine to 



posterior side P 4 23.8 mm. 



Height of mandible below protoconid of M t .. 8 

 P,, antero-posterior diameter 4.5 



P 4 , antero-posterior diameter 6.2 5.9 7 



M 1; antero-posterior diameter 8.2 7.9 10.5 



M 1( antero-posterior diameter of heel 2.7 2.7 3.6 



A skull fragment (No. 584, see measurements above) showing 

 a perfect inferior sectorial with P. ; , P 4 , the trigonid of M 1? and 

 a part of the first upper molar represents an animal considerably 

 larger than the typical C. ( ?) oregonensis. The form of the teeth 

 is much the same as in oregonensis and is quite different from 

 that in latidens and geismarianus. I think it is very doubtful 

 whether this form belongs in oregonensis, but the amount of vari- 

 ation shown in all the groups of John Day dogs is so great that I 

 hesitate to separate it until more is known concerning it. 



5 See p. 16, this paper. 



