5i6 



UNGULATES. 



likewise in their general mode of life. The lophiodons are somewhat older animals, 

 being mainly characteristic of the middle Eocene strata of Europe. Some of them 

 were as large as a rhinoceros ; and their upper molar teeth approximate to those of 

 the tapirs having their outer columns conical, instead of assuming the flattened form 

 characteristic of the palseotheres. The lower molars, moreover, differ from those of 

 the palseotheres in having their transverse ridges nearly straight instead of crescent- 

 like ; and the total number of teeth is only forty, owing to the loss of the first 

 premolar in each jaw. So far as known, the number of toes to the feet was the 

 same as in the tapirs ; and while the true lophiodons apparently indicate a group 

 which died out without leaving any descendants, certain allied forms probably 

 indicate the ancestral stocks of both the tapirs and the rhinoceroses. 

 Titanotheres and In the Miocene period there existed in North America and the 

 Chaiicotneres. Balkans certain gigantic rhinoceros-like Ungulates, which, while 

 belonging to the Odd-toed group, were quite unlike any other forms, and approxi- 

 mated in bulk to the elephants. These titanotheres, as they are called, had skulls 

 somewhat like those of rhinoceroses, but furnished with a pair of bony processes 

 placed transversely in the region of the nose, which were doubtless furnished 

 with horny sheaths during life. The limbs were massive, and furnished with 

 four toes in front, and three behind, one of the fore-feet being figured on p. 152. 

 Some of the species had the full number of forty-four teeth, placed in close 

 apposition to one another; but in others the whole of the lower and one pair 

 of the upper incisors were wanting. The molar teeth are of the type of those 

 shown in the accompanying figure, and differ very markedly from those of other 

 Odd-toed Ungulates ; they consist of four columns, of which the outer ones are 

 flattened, and those on the inner side more or less conical. The teeth are further 



remarkable for the extreme lowness of 

 their crowns. North America also yields 

 remains of smaller but allied Ungulates, 

 such as Palmosyops, which extend down- 

 wards to the highest beds of the Eocene, 

 and have no bony processes on the skull. 



The most extraordinary modification 

 of the Odd-toed Ungulate type is, however, 

 presented by the chalicothere, which is 

 common to the Pliocene and Miocene 

 deposits of Southern Asia, Europe, and the United States. In these animals the 

 molar teeth were of the type of the titanothere ; but the limbs terminated in long 

 curved claws, very similar to those of the pangolins or scaly ant-eaters, described in 

 the next volume. Indeed, so like are the limbs of the chalicothere to those of the 

 last-named animals, that they were originally regarded as indicating a member of 

 the same group. Apparently, however, the chalicotheres must be regarded as 

 specially modified Ungulates, more or less closely allied to the Odd-toed group, and 

 adapted for a fossorial, or possibly arboreal mode of life. 



/ '2 



TWO EIGHT UPPER MOLAR TEETH OF 



PALiEOSYOPS. (From Earle.) 



