192 CRITIQUES AND ADDRESSES. [ix. 



drawn up similar schemes for the Oxen and other 

 Ungulata with what, I am disposed to think, is a fair 

 and probable approximation to the order of nature. But, 

 as no one is better aware than these tAVO learned, acute, 

 and philosophical biologists, all such arrangements must 

 be regarded as provisional, except in those cases in 

 which, by a fortunate accident, large series of remains 

 are obtainable from a thick and wide-spread series of 

 deposits. It is easy to accumulate probabilities hard 

 to make out some 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 Anclii- 

 therium j 1 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 Palczotherium, especially Cuvier s Palceotherium minus, 

 which has been formed into a separate genus, Plagio- 

 lophus, 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 



1 Hermann von Meyer gave the name si Anchitherium to A. Ezyucrrte; 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 Paltcotherium d* Orleans. But it is precisely 

 the Palteotherium d Orleans which is the type of Christol s genus Hippari- 

 theriam ; and thus, though Hipparitherium is of later date than A)ichithennm t 

 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. 



