250 BULLETIN 169, UNITED STATES NATIONAL MUSEUM 



M^ from Loc. 82 (American Museum), and specimens figured by 

 Douglass (1902b, p. 222) from Loc. 5 or 6. These specimens vary- 

 considerably among themselves, and they are not clearly distinguish- 

 able from variants of T. puercensis, but they are inadequate for 

 specific determination and do not definitely establish the presence of 

 that species in this field. 



The original of Douglass' 1908, pi. 1, fig. 4, is perhaps a right P^ 

 of this same form, but this is uncertain, and the other isolated teeth 

 referred to Tetraclaenodon by Douglass seem still more dubious. 



There are also preserved with U.S.N.M. no. 11913 a right and a 

 left M^ (possibly M^) probably of Tetraclaenodon and, at least in their 

 worn condition, closely resembling T. puercensis. They certainly are 

 not associated with no. 11913, since they are from a much older indi- 

 vidual, and it is very improbable that they are of the same species, 

 and not at all clear that they are congeneric. No. 11913 is recorded 

 as from Loc. 11 or 13. These localities are at about the same level 

 and are the highest that have yielded identifiable mammals. A note 

 by Silberling with the specimens seems to leave little doubt that 

 these specimens were derived from that level except in the highly 

 improbable case that they have accidentally been substituted for 

 two other upper molars in the collection.* Tetraclaenodon has not 

 otherwise been reported from beds as late as this, and these teeth 

 are inadequate to establish its presence although they make it 

 probable. 



Genus GIDLEYINA Simpson* 

 Gidleyina Simpson, 1935d, p. 240. 



Type. — Gidleyina montanensis (Gidley). 



Distribution. — Upper Paleocene, Fort Union, Montana. 



Diagnosis. — Gidley '°: "Cheek teeth bunolophodont; first and sec- 

 ond upper molars subquadrate, consisting of four principal cusps, 

 two intermediates, and a well-developed mesostyle, conules con- 

 nected by continuous lophs with the summit of the protocone; pre- 

 molars 3 and 4 with well-developed protocones, but with metacones 

 rudimentary; thus superficially they each consist of two principal 

 transversely placed cusps." 



8 The teeth themselves are not mnrked, as are most specimens in the collection. 



• In one draft of his manuscript Dr. Gidley referred the type of this genus to Euprotogonia, in another 

 to Ectocion, and in a third, presumably the most recent, to Proedocion, new genus. His new generic name 

 is, however, preoccupied by Proectocion Ameghino, 1904, and therefore it cannot be used. He intended 

 to change it, for he had made a pencil notation, "change name, not related to Ectocion, but rather to Pro- 

 togonodon", but I find no other name in his notes or on his labels and so have been forced to supply one. 

 It is highly appropriate that the genus should be named for Dr. Gidley. (Oidleya Cossman, 1907, is a fossil 

 bovid.) 



>" Quoted from what is probably the most recent draft of Dr. Gidley's manuscript, the only one in which 

 a new genus is proposed. 



