54 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



MEASUREMENTS IN MILLIMETERS OF LOWER TEETH IN 



SPECIMENS OF ProUmnocyon 



p. atavus p. elisabethae P. antiquus P. antiques 



A.M. U.S.N.M. A.M. U.S.N.M. 



No. No. No. No. 



16816 I93SO 14768 22452 



Type Type Type 



Pi-Ms (at alveoli) 35-0 4i-o 4O-0 



P1-P4 (at alveoli) 20.6 25.3 25.0 



Ml- Ma (at alveoli) 14.0 14.0 iS-5 ^S-O 



P», anteroposterior diameter : 



transverse diameter 5-0 : 2.1 4.9 : 2.1 



Pa, anteroposterior diameter : 



transverse diameter 5-4 : 2.0 



P4, anteroposterior diameter : 



transverse diameter 5.8 : 2.6 6.3 : 2.9 



Ml, anteroposterior diameter : 



transverse diameter 6.2 : 3.4 5.9 " : 3.0 * 6.4 : 3.5 



M2, anteroposterior diameter : 



transverse diameter 6.4 : 4.2 6.8 : 3.5 7.0 : 4.0 



Ms, anteroposterior diameter : 



transverse diameter .... 2.6 : 1.7 



• Approximate. 



HYAENODONTIDAE 

 SINOPA, possibly S. VIVERRINA (Cope) 

 (Plate 6, figure 3) 



A pair of louder jaws (U.S.N.M. No. 22456) of a decidedly small 

 species of Sinopa was found in the La Barge level of the Knight beds 

 about 12 miles north of Big Piney. Most of the teeth are preserved 

 although some are slightly damaged. Direct comparison with Cope's 

 type of the New Mexican species Sinopa viverrina is not feasible 

 because, not only were there no lower teeth included, but the palatal 

 portion, exhibiting the upper dentition figured by Cope (1877, pl- 2>^> 

 fig. i), has been missing from the type material (U.S.N.M. No. 1022) 

 for some time. Nevertheless, from the measurements given by both 

 Cope and Matthew for these upper teeth, it seems that the proportions 

 of the lower teeth in the Knight specimen are entirely compatible for 

 proper occlusion. 



The lower molars in No. 22456 are characterized by talonids having 

 a very weak, posteriorly placed entoconid and almost no lingual crest 

 or ridge forward from the entoconid position. The talonid basin 

 slopes steeply to the lingual margin of the tooth, reaching a climax 

 in Ms where the narrow, elongate talonid is essentially without a basin. 

 It may be further noted that the anterior premolars follow the canine 



