60 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



Cf. VULPAVUS AUSTRALIS Matthew 



(Plate 8, figure 5) 



A single upper molar (U.S.N.M. No. 22474), much larger than 

 in the Bitter Creek maxilla thought to be of Vulpavus, was found in 

 association with Heptodon high on the slope of Fossil Butte. The tooth 

 is rather dose in size to M^ in the Gray Bull specimen (A.M. No. 

 16954) referred to V. australis. The protoconule, however, is a little 

 less lingual and the cingulum is not as heavy. A slight mesostyle on 

 No. 22474 cannot be determined for M^ of No. 16954 because of 

 slight damage to this portion of the tooth, but it is lacking in M^ of the 

 Gray Bull specimen. 



VULPAVUS ASIUS Gazin 



(Plate 8, figures 2 and 3) 



Three additional specimens of Vulpavus asius bring the total to 11 

 that now represent this species in the La Barge fauna. One of these 

 (U.S.N.M. No. 22470), a lower jaw including the first two molars, 

 was collected by Privrasky west of Big Piney. The other two are 

 isolated Mg's from 12 miles north of Big Piney. Mention should also 

 be made of an incomplete lower molar, surely of this species, from 

 approximately 150 feet beneath the Tipton tongue about 13 miles 

 north of Baggs, Wyo., one of the more productive localities for 

 material of the Dad fauna. 



A somewhat larger mutant, evidently of Vulpavus asius, is repre- 

 sented by four specimens from the New Fork tongue. One of these, 

 U.S.N.M. No. 22471, includes both rami of the mandible and repre- 

 sentation of P4-M2. A composite of the teeth from both sides is shown 

 for the left ramus in plate 8 (fig. 2) in comparison with the type 

 (fig. 3) from the La Barge faunal level 12 miles north of Big Piney. 

 The teeth in No. 22471 are among the larger for the New Fork mutant, 

 which average a little larger than in the La Barge form. The observed 

 ranges in size, however, do overlap. The depth of the jaw in No. 22471 

 is about the same as in the La Barge type. 



The New Fork mutant makes a close approach in size to contem- 

 porary Lost Cabin Vulpavus canavus as represented, for example, 

 by the comparatively small type specimen of V. brevirostris (Cope), 

 and the lengths of the lower molars in No. 22471 can be nearly 

 matched in certain of the Wind River specimens. P4, however, is 

 distinctly smaller and all the teeth are relatively narrower. The New 

 Fork materials might have been allocated to V. canavus but they are 



