. Annals of the Carnegie Museum. Carnegie Museum; Carnegie Museum of Natural History; Natural history. 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
. Annals of the Carnegie Museum. Carnegie Museum; Carnegie Museum of Natural History; Natural history. 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 ba
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