326 E. L. Troxell — American BofJiriodonts. 



to re-adopt the name Bothriodon Aymard (syn. Ancodus 

 Pomel, Hyopotannis Owen) in agreement with Professor 

 Marsh and Miss Bush. Nor is it a misfortune to follow 

 A^miard in this respect, for it is to him we have to turn 

 for the early descriptions of this group of the anthraco- 

 theres. Kowalevsky^ says in 1874: 



"The priority . . . is claimed by Pomel . . . but as he neither 

 gave a good description . . . , nor illustrated his short notices 

 by figures, no paleontologist has accepted this name, and it may 

 be considered extinct." 



He therefore proceeds to use the name Hyopotannis 

 instead. 



Filhol/"^ although he continues to use the term Ancodus, 

 yet agrees that we owe it to the researches of Aymard 

 alone, carried on so long at Ronzon, that we have the 

 necessary material to trace the group completely. 



Relationship to foreign types. — It is not profitable at 

 this time and in such a paper as this, to go deeply into 

 the study of the Old World faunas. Kowalevsky,'^ after 

 comparing the British . specimens of Hyopotannis with 

 those of Bothriodon (Ancodus) of the continent, says 

 that he can find no noteworthy distinctions. But in the 

 seemingly great variety of European forms, it is evident 

 that no one genus can be so broad as to include all the 

 species, and one is led to believe that a careful study would 

 establish the authentic separation of Bothriodon and 

 Hyopotamus at least, and might even create the need for 

 additional genera. In fact, there seems to be nearly as 

 much difference between H. hovinus Owen and H. vectia- 

 nus Owen as there is between the latter and some species 

 of Elomeryx, and doubt lingers as to whether even the two 

 English forms should be included under the same head. 



Desckiptiox of Genera. 



Anthracotheriuni Cuvier. — The distinctions between 

 certain New and Old World forms are listed under the 

 description of ^pinacodon, gen. nov., later. The differ- 

 entiation of Anthracotheriuni, A. niagnuni Cuvier, may 

 here be briefly set forth: It is a very large animal 

 ranging in size to a half larger than our American forms, 

 as shown by De Blainville. P^ has a heavy deuterocone 



* W. Kowalevsky, Philos. Trans. Eoy. Soc. London, 163, 22. 

 ^ H. Filhol, Aiin. Sei. Geol., 12, art. 3, 191, 1881. 

 « Op. cit., p. 23. 



