XI PALAEONTOLOGY AND EVOLUTION 355 



particular case in such a way that it will stand 

 rigorous criticism. 



After much search, however, I think that such 

 a case is to be made out in favour of the pedigree 

 of the Horses. 



The genus Equus is represented as far back as 

 the latter part of the Miocene epoch; but in 

 deposits belonging to the middle of that epoch its 

 place is taken by two other genera, Hipparion and 

 Anchitherium ; l and, in the lowest Miocene and 

 upper Eocene, only the last genus occurs. A 

 species of Anchitherium was referred by Cuvier to 

 the Palceotheria under the name of P. aurelianense. 

 The grinding-teeth are in fact very similar in 

 shape and in pattern, and in the absence of any 

 thick layer of cement, to those of some species of 

 Palceotherium, especially Cuvier's Palceotherium 

 minus, which has been formed into a separate 

 genus, Plagiolophus, by PomeL But in the fact 

 that there are only six full-sized grinders in the 

 lower jaw, the first premolar being very small; 

 that the anterior grinders are as large as, or 

 rather larger than, the posterior ones ; that the 



1 Hermann von Meyer gave the name of Anchithcrium to A. 

 EvpierroR ; and in his paper on the subject he takes great pains 

 to distinguish the latter as the type of a new genus, from 

 Timer's Palceothcrium cTOrltona. But it is precisely the 

 Pnlceotherium d'OrUan* which is the type of Christol's genus 

 Jlijrparitherium ; and thus, though JJipjxiritherium is of later 

 date than Anchithtrium, it seemed to me to have a sort of 

 equitable right to recognition when this Address was written. 

 On the whole, however, it seems moat convenient to adopt 



