COPE.] PALEONTOLOGY MIOCENE PERIOD. 507 



Measurements. 



M. 



Length of molar series 0.036 



Length of premolar series 019 



Length of fourth premolar 006 



Length of sectorial -.009 



Width of sectorial 004 



Height of sectorial 006 



Depth of ramus at sectorial 010 



This species is more abundant than all the other carnivora of the Col- 

 orado beds together, and is the only one that bears due proportion to 

 the numbers of rodentia, on which it no doubt depended for food. 

 Slight and unimportant variations may be observed among the numer- 

 ous specimens. 



This species is about the size of the AmpMcyon gracilis, Leidy, from 

 the White Eiver beds of Dakota, and I suspected at one time that I had 

 found that species in Colorado. Dr. Leidy describes that dog as having 

 a two-rooted second tubercular molar, a character befitting its reference 

 to Amphicyon, but very distinct from anything found in Canis gregarius. 

 Leidy's figure (7-8, PL v) exhibits also an equality in the size of the in- 

 cisor-alveoli and production of the premasillary bone not found in the 

 present species. 



Canis osoeu:.i. Cope, Synop. Yert. Col., 1873, p. 10. 



Eepresented by two mandibular rami of a species of about the size of 

 a weasel. One of these exhibits four premolars, the other a fourth pre- 

 molar with fangs of a sectorial, and one or tv/o tubercolars. The first 

 premolar is one-rooted and close behind the large canine ; the third 

 exhibits no posterior lobe, and the crown is low. The ramus is shallow 

 and stout. 



In the second specimen, which is only provisionall3' referred here, the 

 proportion of the base of the crown of the fourth premolar is identical 

 with that of the first-described specimen. It exhibits a posterior me- 

 dian lobe. 'The succeeding tooth was a little larger, and the first root 

 following placed transversely in the jaw. 



Measurements. 



Length of bases of four premolars, (No. 1) 0.0113 



Length ol basis of P. a:. Ill 0030 



Elevation of crown of P.m. Ill 0020 



Length of basis of crown of P. m. IV 0040 



Depth of ramus of mandible at P. ru. IV OOCO 



Length of bases of P. m, IV, M. I 0080 



Depth of ramus at hrst molar 0060 



BUiirjaLUEUS, Cope. 



Synopsis Vertebrata Colorado, 1873, p. 8. 



Char. gen. — Molars two, the first sectorial and without inner tubercle j 

 the second small, tubercular. Premolars simple, acute; .mandible not 

 widening forward. This is one of the forms which associates the Fclida; 

 and Mustelida\ With the tubercular tooth of the latter, the sectorial re- 

 sembles that of the cats, in the absence of all ti-ace of the inner tuber- 

 cle, but is ugain weasel-like in the well-developed heel of the sectorial. 

 The genus is probably without the peculiarities of the Drcpanodons, &c., 

 i. e., the downward expansion of the mandible, &c. The genus jElurogaJc, 



