20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I3I 



DILOPHODON Scott, 1883 



Dilophodon was described by Scott (1883) in tbe same publication 

 as Desmatotherium and, as in the case of D, giiyotii, the type of 

 Dilophodon minusculiis was attributed to the Bridger Eocene. It is 

 clear that Scott regarded the Washakie beds as Bridger and it is from 

 the Washakie Basin rather than the Bridger Basin, as indicated by 

 Granger ( 1909, p. 22), that the D. minuscidus type originated. Granger 

 has the species listed as representing Washakie A, but I suspect that 

 the horizon for this, as well as D. guyotii, is B, particularly since both 

 are known from the upper Eocene elsewhere and neither has turned 

 up in the rather extensive collections known from the Bridger proper. 



Dilophodon is clearly related to Helaletes but represents a line 

 separate from that of Desmatotherium, possibly derived from the 

 species Helaletes hoops, having the less progressive premolars or, as 

 seems more than likely, from a somewhat earlier stage. It is not cer- 

 tainly demonstrated that Dilophodon gave rise to Protapirus but, as 

 far as can be determined, this upper Eocene form possesses all, or 

 nearly all, the requirements in the structure of the teeth that might be 

 sought for in the Eocene ancestor of the true tapirs. 



DILOPHODON, cf. LEOTANUS (Peterson), 1931 

 Plate I, figures 7, 8 



The type of Peterson's Heteraletes leotanus from the Randlett lo- 

 cality exhibits beyond doubt an immature dentition so that the char- 

 acters attributed to the premolar series, particularly the "molariform 

 P4," apply to the deciduous series, and hence do not serve to dis- 

 tinguish Heteraletes from Dilophodon. 



In the Badwater collection there is a right mandibular ramus 

 (U.S.N.M. No. 20207, figured by Hough, 1955) including all the 

 lower cheek teeth, and both maxillae of a skull (U.S.N.M. No. 21098) 

 with P^-]VP represented, although P*, M\ and M^ are not complete. 

 There are in addition almost a dozen isolated teeth or portions of teeth. 

 Comparison between the Badwater and Randlett materials is limited 

 to Ml and IMg. These teeth in No. 20207 ^r^ close in size to those in 

 the type, although possibly a trifle wider, and have similar completely 

 lophoid transverse crests with practically no development of a crista 

 obliqua. 



The Badwater form clearly represents a species with smaller teeth 

 than the Washakie Dilophodon minuscnhis, but the lower jaw is deeper 

 and a little more robust. Moreover, the symphysis is broader and ex- 



