TRANSACTIONS OF WAGNER 

 48 



UINTA SELENODONTS 



have been applied to this genus. In what follows I assume that Dr. Wortman's 

 identification of Leptotragulus with " Paramcryx' 'is correct, for he has seen the 

 type specimens, and that my use of the latter name for Protylopus is a mistake. 

 ('98, p. 74.) At the same time I cannot but feel some doubts as to the correct- 

 ness of the identification, the reasons for which doubts will be explained below. 



Professor Marsh (loc. cit.) proposed the name "Pardmeryx," in the course 

 of an address upon the "Introduction and Succession of Vertebrate Life in 

 America," without any definition, without any figures, not assigning any 

 species to the proposed genus, and not indicating in any way that he was 

 establishing a new genus, or that the name was used for the first time. The 

 only references made to the animal in the course of the address are as follows : 

 " With this' genus is another [Parameryx) also closely allied to Homacodon, 

 but apparently a straggler from the true line, as it has but three toes behind." 

 ('77> P- 364-) " A most interesting line, that leading to the camels and llamas, 

 separates from the primitive selenodont branch in the Eocene, probably through 

 the genus Paramcryx." (Ibid., p. 365.) From such vague allusions as these it 

 is obviously impossible to identify the genus referred to, and according to 

 all the codes of nomenclature the term must be regarded as the baldest 

 nomen nudum, and has no standing whatever. This is especially true be- 

 cause the single hint of a diagnostic character which is given in the account, 

 namely, the alleged presence of three toes in the pes, is probably erroneous. 

 When the name Leptotragulus was proposed the authors had no means of 

 determining whether or not it was the same as " Paramcryx," and thus 

 were compelled to employ a new term. Seventeen years after his first use 

 of the term Professor Marsh published a very vague and meagre description of 

 "Paramcryx" ('94, p. 269), together with figures of an isolated upper molar 

 and of the astragalus. So far as it goes, this description will apply quite as 

 well to Protylopus as to Leptotragulus, and hence my use of the name for the 

 former in my preliminary paper. ('98.) 



It was stated above that I do not feel entirely satisfied that the two gen- 

 eric terms, Leptotragulus and Paramcryx, actually refer to the same genus- 

 Professor Marsh's figure of the astragalus ('94, p. 268, fig. 21), if correctly 

 referred to the same animal as the upper molar (fig. 20), indicates a form of 

 totally different proportions from those of Protylopus. While the molar is of 

 about the same size as in the latter genus, the astragalus is far larger and 

 equals that of Protorcodou in size. It seems unlikely that the astragalus can 

 be correctly associated with the tooth, and if they belong to different individ- 



