40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I3I 



Horizon and locality. — Bison basin Tiffanian, Titanoides locality, 

 southwestern portion of basin, sec. 29, T. 27 N., R. 95 W., Fremont 

 County, Wyo. 



Specific characters. — Lower molar teeth about 15 percent longer 

 and nearly 22 percent wider transversely than in Haplaletes pelicatus. 

 Paraconid on M2 and M3 vestigial. Talonid basin shallow. Hypo- 

 conulid of M3 broader and less protruding posteriorly. No external 

 cingulum. 



Discussion. — The type of Haplaletes serior is the only known speci- 

 men and comes from near where the Titanoides upper teeth were dis- 

 covered, about a mile west of the saddle locality, and apparently a 

 little higher stratigraphically. 



Haplaletes serior is a larger form than H. pelicatus with relatively 

 wider molars. The form appears, from the limited material, to repre- 

 sent the same genus as H. pelicatus but would seem more distinct 

 from H. disceptatrix. However, the difference from the latter is for 

 the most part a rather marked disparity in size. 



MEASUREMENTS IN MILLIMETERS OF TEETH IN TYPE SPECIMENS OF 



TWO NEW SPECIES OF Haplaletes 



H. pelicatus H. serior 



U.S.N.M. U. of Wyo. 



No. 21008 No. 1078 



(type) (type) 



Ps, anteroposterior diameter : greatest transverse 



diameter 2.6° : 1.6° 



P4, anteroposterior diameter : greatest transverse 



diameter 3-3 : 2.0 



Ml, anteroposterior diameter : greatest transverse 



diameter 30 : 2.3 



Ma, anteroposterior diameter : greatest transverse 



diameter 3.2 : 2.8 37 : 3-4 



M3, anteroposterior diameter : greatest transverse 



diameter 3-3:2.6 37: 3-1 



" Approximate. 



PROTOSELENE? NOVISSIMUS,i' new species 

 Plate 8, figures i, 3 

 Type.—Ltii ramus of mandible with Mo and M3, U.S.N.M. 

 No. 20572. 



Horizon and locality. — Bison basin Tiffanian, saddle locality at 

 south rim of Bison basin, sec. 28, T. 27 N., R. 95 W., Fremont 

 County, Wyo. 



17 Noi'issimns = youngest or latest, with reference to the stratigraphic horizons 

 for Protoselene. 



