54 Annals of the Carnegie Museum. 



curved. There is a slight groove near the base on the antero-internal 

 angle, otherwise the enamel is quite smooth. Pi has a single sharp 

 conical crown. P^ is implanted by two roots ; it has a high and sharp 

 protocone and a very small posterior basal lobe. P-3. is similar to P-^, 

 but somewhat larger, and possesses a slightly more pronounced pos- 

 terior basal lobe, and a rounded and smooth external cingulum. The 

 greatest difference between these forms and those from the John Day 

 formation is in the proportions of the fourth premolar (carnassial). 

 This tooth has a greater antero-posterior diameter than in Nothocyon 



Fig. 14. Side view of upper and lower jaws of Nothocyon annectens Peterson. 

 Natural size. Type, No. 1602. 



geis??iariamis, though the latter species is of considerably larger size. 

 In the present species P± is surrounded by a cingulum and also has a 

 fairly well developed deuterocone. The protocone and the postero- 

 external blade are well developed and the fissure separating them is 

 well marked. Mi has six tubercles on the grinding face ; two ex- 

 ternal, equal in size ; the anterior median large, while the posterior 

 median is only a mere rudiment. The internal cingulum is developed 

 into two equal-sized tubercles which are divided by a shallow fissure. 

 The external cingulum is heavy and rounded. On M^ the anterior of 

 the external pair of cusps is the larger of the two ; the median V- 

 shaped ridge is somewhat similar to that in N. lemur, but its internal 

 apex terminates in a tubercle, and there is in the present species a 

 minute tubercle posteriorly in the median valley. The cingulum is 

 very heavy internally, while externally it is not so well developed. 



The mandible is slightly shallower than in N. lemur. The inferior 

 border is evenly rounded from before backward to opposite M3-, where 

 the border rapidly ascends upwards and backwards, then more directly 

 backwards, and forms a strong angle. The posterior exit of the den- 



