ART. 1. PRIMATES OF THE FORT UNION — GIDLEY. 7 



The upper molars referred to this species show the following char- 

 acters: Cusps in general moderately high, median cuspules conspicu- 

 ous; protocones relatively high and pointed. They differ also from 

 those of the species of Faromomys in having the inner posterior por- 

 tion of the base relatively less expanded and the posterior face of 

 the protocone more steeply sloping. The area bounded by the meta- 

 loph, the angulated ridge formed by the posterior basal cingulum, 

 and the continuing ridge from the apex of the protocone, is less dis- 

 tinctly basined. Measurements of upper molars — m^ to m^ = 5 mm. 



PALAECHTHON MINOR, new species. 



Plate 4, Figure 1. 



Type. — Greater portion of a right lower jaw carrying four teeth, 

 P4 to 100.3, aod the alveoli for pg and apparently for a canine and an 

 incisor. (Cat. No. 9639, U.S. N.M. Coll.) Collected by A. C. Silber- 

 ling. The species is also represented in the collection by a few other 

 specimens, including two upper jaw portions. 



Locality and horizon. — Same as for Paromomys maturus. 



Specific characters. — ^P4 to m3 = 5.3 mm.; m, to m3 = 4.3 mm. 

 About one-third smaller than P. alticuspis, with apparently a reduc- 

 tion of premolars to two instead of three, but with canine of moder- 

 ate size and an enlarged incisor as in the species described above. 



This is by far the smallest species of the Paromomys-Palaechthon 

 group, and while conforming in general characters with the others, it 

 differs in so many details that its reference here is only 

 provisional. Unfortunately all the jaws in the collection 

 representing this species either have the anterior portion 

 wanting or are broken in that region in such a way as to ^^^ ^ -pala- 

 obscure the modifications that have taken place in the kchthon mi- 

 anterior teeth. It is certain, however, that the enlarged f°^" ^ ^^^' 



' ' c5 lES OF THREE 



incisor was laterally compressed and was decidedly more upper mo- 

 procumbent than in other species of the group, and that leTt°sidT 

 P2, as well as pi, is wanting. P3 is reduced about as x4/i. cat. 

 in the other species, but p^ is a high cusped, very ^o-^^^o. 

 much shortened tooth which, except for its shorter heel, more 

 nearl}^ resembles the corresponding tooth in species of Nothodectes. 

 The lower molars closelj resemble those of P. alticuspis, both in the 

 relative height of the trigonids and the distinctness and position of 

 the paraconids. M3, however, differs from that of P. alticuspis in 

 having a narrow, single-cusped heel. 



A series of three upper molars of the left side (Cat. No. 9590) 

 and a fragment of a left maxillary carrying m^, m^ (broken), and 

 the alveoli of m^ (Cat. No. 9595), seems to be properly referable to 

 this species. These teeth, more than the lower ones described, pre- 

 sent the general characteristics of the genus, differing from those of 



