157 



difference of level between the base of the cranium and the palate ; 

 and to the inner side of the posterior molars there is just sufficient qf 

 the matrix removed to show a slightly raised curved Une whose place 

 is about that which the edge of the posterior nasal opening should 

 occupy, if the animal be organized upon the true Perissodactyle 

 type. A further confirmation is afforded by the distinct appear- 

 ance of a groove, whose broken edges testify the loss of the little 

 piece with which the alisphenoid canal shoidd be enclosed ; so in 

 the only fragment we possess every character that remains agrees, . 

 to help us through the difficulty in which the ambiguous dentition 

 leaves us. 



May I be permitted to express the hope, that before forming a de- 

 cided judgement on these matters, naturalists will carefully investigate 

 for themselves ; recollecting, that so long as man is not infallible, the 

 continued progress of research must with new discoveries find some- 

 thing to be corrected in that which has been done before ? but what- 

 ever be the judgement on these points of difference, I trust that doubts 

 will cease as to the truth of the original idea, which nought but error 

 hindered from being sooner developed ; and that one important step 

 may thus be gained towards that correct appreciation of the compa- 

 rative value of groups, which we must attain throughout organic na- 

 ture, before further generalizations can safely be attempted. 



I will conclude by giving a list of genera arranged as I should now 

 propose ; the characters of the groups, although many remain to be 

 discovered, are already too numerous to be again repeated, and I only 

 include such genera of which I have been able to examine skulls ; or 

 in the case of fossils, of which actual specimens, casts, or well-authen- 

 ticated figures of some characteristic portion of the skeleton have come 

 within my observation. 



ARTIODACTYLA. 



RUMINANTIA. NON-RUMINANTIA. 



Merycopotamus. Hippopotamidfe. 

 Chaiicotherium * . Hippopotamina. 

 Bovidte. Hippopotamus. 

 Sivatherium. Hyopotamus. 

 Anthracotherium. 



Bos. Choeropotamus. 



Ovis. Adapis. 



Capra. Dicohjlina. 



Antilope, and several of Dicotyles. 



the genera into which 

 these have been dis- 

 membered. 



• Of these two genera I have not yet sufficient evidence to determine the 

 family. 



