118 Annals of the Carnegie Museum. 



mens, and reveal a mistake, by oversight in the text, since they are 

 correctly indicated in his illustration {op. cit., PI. X, Fig. l). 



Detailed Description and Comparison of the Material. 



P- of the Carnegie Museum specimen has two external tubercles 

 set close together and a small blunt deuterocone not unlike some of 

 the early tertiary forms {Homogalax protapirinum (Wortman) of the 

 Big Horn Wasatch) except that the latter species has the deuterocone 

 located slightly further back and the tooth itself has proportionally a 

 greater transverse diameter than in the present specimen. ^^ P- has 

 two internal tubercles, which are slightly better developed than in 

 Pai'isectolopliiis latidois. The proto- and tritocones are situated close 

 together, the parastyle is ciuite prominent and is separated from the 

 inner tubercles by a deep concavity of the ectoloph. This portion of 

 P- is lost in PariscctoJophus latidens. P- agrees in all its detailed 

 structure, with that tooth in Parisectolophiis latidens. Hatcher has 

 already pointed out that there is only one internal tubercle of P^- in 

 Parisectolophiis latidens^'^ and that Osborn's generic definition of 

 Isectolophus is partly erroneous. ^^ The ectoloph of P- in Isectolophns 

 consists of three subequal swellings, the trito- and protocones, and 

 the parastyle is identical w'ith that in the Bridger species. The 

 molars increase gradually from the first to the last, and they differ 

 in no important degree from those of Parisectolophiis latidens. 



A right maxillary. No. 2337, with the cheek-teeth represented, found 

 by Mr. Earl Douglass in Horizon C, at the Devil's Play Ground near 

 Kennedy's Hole, Uinta Basin, is interesting from the fact that a de- 

 tached small premolar crown, most probably P-, was found with 

 the specimen and is here for the first time recorded. P- of this speci- 

 men is immediately in front of P-, and is two-rooted and the crown, 

 if correctly determined, is rather small, blunt, and conical in shape, 

 with considerable wear from the opposite tooth. The teeth back of 

 P- are identical with, though smaller than, those described in the fore- 

 going pages. From this specimen it also appears quite clear that the 

 infra-orbital foramen is located above the anterior portion of P-. 

 The maxillary is broken off immediately in front of P-. 



The inferior dentition of specimen No. 3030 is represented by the 



'^ P- is lacking in the type specimen of Parisectolophiis. 



^'' Amer. Jour. ScL, Vol. I, 1896, p. 177. 



'J« Trans. ,\mcr. Philos. Soc, Vol. XVI, 1889, p. 519. 



