46 



PROCEEDINGS OF THE NATIONAL MUSEUM 



lingual portion of P* seems more constricted anteroposteriorly and 

 apparently has a less conspicuously developed lingual crescent. 



A. gllUanus has teeth relatively wide transversely, the length of 

 the tooth row shorter, and the hypocone is placed more lingually 

 with respect to the metacone, and to a certain extent with respect 



to the protocone, than in A. 

 sectorius. 



The lower jaw fragments 

 exhibit teeth comparable in 

 size to those in A. sectorius 

 and show no significant differ- 

 ences from them, nor are dif- 

 ferences evident in the pre- 

 served material which would 

 serve to clearly distinguish 

 the Dragon form from A. 

 gillianus. However, the crest 

 connecting the hypoconid to 

 the trigonid appears distinctly 

 lower than that connecting the 

 entoconid to the metaconid. 

 This condition was noted in 

 an Ml of J., gillianus but not 

 in other specimens of either 

 this species or A. sectorius. 

 Moreover, the hypoconulid 

 does not project backward in the molars referred to Anisonchus 

 dracus quite so far as in M2 of A. sectorius^ a condition approxi- 

 mated in M2 of A. gillianus, though possibly of doubtful significance. 



Table 10. — Measurements {in millimeters) of upper teeth {U.8.N.M. No. 15745, 

 type) and lower teeth {V.S.N.M. No. 16249) of Anisonchus dracus 



Figure 25. — Anisonchus dracus Gazin: Left 

 maxillary portion with P*-M» (U.S.N.M. 

 No. 15745), type specimen, lateral and occlusal 

 views, X 3. Dragon Paleocene, Utah. 



ANISONCHUS ONOSTUS ^5 Gazin 



Anisonchus onostus Gazin, 1939b, p. 280. 



The smaller of the two species of Anisonchus in the Dragon fauna 

 is represented by the type, No. 15788 (fig. 26), which is a lower 

 jaw portion with Mi and M,, and to the species is tentatively referred 

 an upper premolar and a lower jaw fragment with the teeth P4, 

 M], and part of M^ much worn. 



25 Onostus, despicable, in allusion to its size. 



