212 Wortman — Studies of Eocene Mammalia in the 



canine, two premolars, and three molars, principally for the 

 reason that the alveolus for the third tooth is enlarged after 

 the manner of a canine, while the two in advance of it are 

 small and hence have been thought to represent incisors. This 

 determination is very probably correct, but it can not be 

 accepted as final until the upper teeth are fully known: The 

 extreme reduction in the number of premolars is a condition 

 more advanced than that found in any other species of Primate, 

 either living or extinct, in the Western Hemisphere ; and that 

 it should have taken place as early as the Eocene is indeed 

 remarkable. In agreement with this reduction, it may be 

 noted, however, that the structure of the lower molars is 

 further advanced than that of any of its contemporaries in the 

 Bridger. This is seen in the loss of the anterior cusp of the 

 trigon from all the molars, and their consequent reduction to 

 the four-cusped stage. I have already called attention to cer- 

 tain resemblances in the structure of the molars between 

 Anaptomorphus and Euryacodon, but the former exhibits a 

 greater advance in the modification of these teeth. . 



A second species, A. homunculus, was described by Cope 

 from the now famous cranium found by me in the Basin of the 

 Big Horn, in 1881. This cranium, together with a second 

 specimen (No. 41 of the American Museum collection) which 

 I also discovered in 1891, in the same region, has recently been 

 reh'gured by Osborn.* These drawings are beautifully exe- 

 cuted, but it is to be regretted that the skull is represented as 

 complete in front, which is by no means the case. Osborn's 

 figure gives the impression that the face is as much shortened 

 and as reduced as in the highest type of living ape. Cope's 

 original figure, in his Tertiary Yertebrata, is far more accu- 

 rate in that it represents the entire anterior portion of the 

 skull as missing. After a most careful study of the remains 

 of this species in the American Museum collection, I find my- 

 self unable to agree with Cope in regard to the dentition of the 

 cranium in question, or with Osborn concerning the dentition 

 of the additional specimens. Cope determined the premolar 

 dentition of the upper jaw to be two, and Osborn gives the 

 number of lower premolars as three. The facts may be briefly 

 stated as follows : In the cranium, there is evidence of the 

 presence of seven teeth ; of these, three are undoubtedly molars, 

 and the remainder incisors, canine, and premolars ; the most 

 anterior tooth indicated is represented by an alveolus ; the next 

 is a pointed single-rooted tooth separated by a short diastema 

 from those behind ; the two following teeth are undoubtedly 

 premolars, with single external and internal cusps. 



* American Eocene Primates, Bull. Amer. Mus. Nat. Hist., 1902, p. 200. 



