326 XOTES ox the canid.e of the white river oligocene. 



the genus Daphcenus Leidy, which has long been known, though hut very imperfectly, and 

 several partially preserved skeletons permit an almost complete account of its osteology to 

 be given. 



DAPH.ENUS Leidy. 



Proc. Acad. Nat. Sci. Phil., 1853, p. 393. Amphicyon Leidy {non Pomel), ibid. 

 1854, p. 157 ; Ext. Mamm. Fauna Dak. and Nebr., 1869, pp. 32, 359 ; Cope, Ter- 

 tiary Vertebrata, pp. 894, 896. Canis Cope, Ann. Rep. U. S. Geoloy. Sure Terrs., 

 1873, p. 505. 



This genus represents nearly the most primitive type of dogs which has so far been 

 determined from the Tertiary deposits of North America. It was originally described 

 and named by Leidy, who afterward mistakenly referred it to the European genus 

 Amphicyon, a reference which was also adopted by Cope. Though more than forty 

 years have thus elapsed since the first discovery of these animals, singularly little has 

 been known about them, for the material obtained has been very scanty and Very badly 

 preserved. Fragments of jaws, a few very imperfect skulls and fewer Hmb-bones have 

 hitherto been the only specimens found, in spite of long and careful search, and beyond 

 the fact that Daphcenus was apparently a primitive member of the canine phylum, little 

 could lie predicated of it. 



The new material gathered by Messrs. Gidley and Wells fortunately removes this 

 difficulty and gives us information regarding nearly all parts of the skeleton of these 

 curious animals. These skeletal characters are of a very surprising nature and their 

 interpretation is by mi means easy. Especially remarkable are the many points of 

 resemblance which we find between the structure of Daphcenus and the corresponding 

 parts of such primitive Machairodonts as I)ini<-li.<. Aside from the dentition and the 

 shape of the mandible, these resemblances in structure between the primitive dogs and 

 the early sabre-tooth eats are ubiquitous, and recur in the structure of the skull, of the 

 vertebrae, of the limbs and of the feet. To bring out the full force of these remarkable 

 characteristics, it will be necessary to enter into a detailed and somewhat tediously minute 

 description of the osteology of Daphaums, so that the means of comparison may be com- 

 pletely laid before the reader. 



I. The Dextitiox. 



The dental formula of the genus is 1 |, (' j. P -j, M -:}, the same as that of Amphi- 

 cyon, a resemblance which caused the erroneous identification of the two genera already 

 referred to. 



A. Upper Jaw (PI. XIX, Fig. 2). — The incisors are closely crowded together and 

 form a nearly straight transverse row ; they are smaller and occupy less space both 



