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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 Pcdceothcria under the name of P. aurclianense. 

 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 

 Palcvothcrium, especially Cuvier s Palccothcrium 

 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 Anchitherium to A. 

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

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

 Cuvier s Palccotkerium d Orleans. But it is precisely the 

 Palccothcrium d Orleans which is the type of Christol s genus 

 Hipparitficrium ; and thus, though Hippariihcrium is of later 

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

 equitable right to recognition when this Address was written. 

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

 Anchitherium. 



A A 2 



