E. L. Troxell — American Bothriodonts. 325 



Art XXL— The American Bothriodonts; by Edward 



L. Troxell. 



[Contributions from the Othniel Charles Marsh Publication Fund, Peabody 

 Museum, Yale University, New Haven, Conn.] 



Introduction. 



Seldom do we find instances of genera that have been 

 so variously arranged and classified, or a synonymy and • 

 precedence that have been more discussed than those of 

 the group of extinct artiodactyls which constitute a part 

 of the Anthracotherinse, including the well known names : 

 Ancodus Pomel, Bothriodon Aymard, Elomeryx Marsh, 

 Heptacodon Marsh, Hyopotamus Owen, and Octacodon 

 Marsh. In the present study it has been necessary to use 

 our own American generic names, adding one new one, 

 in order to bring out the distinctions, from the European 

 forms, which exist in every case ; but one can not resist the 

 impulse to attempt to settle the Old World difficulties, 

 and matters of synonymy are no exception. 



Bothriodon {Ancodus, Hyopotamus). — The generic 

 name Ancodus Pomel was made in June 1847, that of 

 Hyopotamus Owen^ in November of the same year. For 

 years it was supposed that Bothriodon Aymard was made 

 in 1848, until Miss Lucy P. Bush^ set forth a very clear 

 explanation of the matter, backed up by evidence to show 

 that Aymard 's publication was not of 1848 as appears 

 on the cover, but of 1846, thus giving his genus the 

 priority. A difficulty raised by Peterson^ about the page 

 reference in Aymard 's paper to a publication by Pomel 

 dated December 21, 1846, may be explained in one of two 

 ways: first, Aymard 's paper came out during the last 

 nine days of December, 1846 ; or second, Aymard had 

 access to the printer's proof of the other paper before 

 December 21. The latter explanation is the more plaus- 

 ible, because the two authors, Pomel and Aymard, appear 

 to have been working in entire harmony. 



Because of these circumstances, it seems necessary 



' W. D. Matthew (Bull. Anier. Mus. Nat. Hist., vol. 26, 6, 1909) states that 

 this genus is preoccupied by Hyopotamus Kaup 1844, a genus of supposed 

 Hippopotami dse not now recognized. 



'L. P. Bush, this Journal (4), 16, 98, 1903. 



* O. A. Peterson, Mem. Carnegie Mus., vol. 4, No. 3, p. 43, 1909. Peterson 

 here erroneously states that Pomel 's article in the Bulletin de la Societe 

 Geologique came out late in 1847. The article itself bears the date of 

 December 21, 1846. 



