560 THE BEIDGEK EPOCH. 



Within the above definition there is room for much variation, which, 

 however, the known genera do not display. They agree in various points of 

 minor importance Thus there is no sagittal crest of the skull, the tem- 

 poral ridges being lateral, and there is a great supraoccipital crest. These 

 crests are more or less furnished with osseous processes or horns. One of 

 these consists in part of the maxillary bone, and stands in front of or over 

 the eye. The nostrils are well roofed over by the nasal bones. There is 

 always a diastema behind the canine tooth in both jaws. Tliere is less 

 difference between the ])remolar and molar teeth in the known genera than 

 in the Pantodonta, and they are all constructed on the same pattern. Thus 

 in the upper jaw the crowns of the molars support two oblique cross-crests, 

 which unite to form a V with the apex inwards. There is no internal cusp 

 or tubercle. The inferior molars consist essentially of an outer Y and a 

 heel; the true molars differ in having the heel a little larger, and more 

 recurved on its posterior bordei', but it does not rise into a transverse crest, 

 as in the Coryiilwdontidoe. Messrs Spier, Scott, and Osborne show that the 

 inferior incisors in Loxolojihodon are compressed and two-lobed. 



In LoxoJophodon the malar bone forms the middle elemenf of the zygo- 

 matic arch, sending a narrow strip only forward to the neighborhood of the 

 lachrymal. In Uintatherium, according to Marsh, its extension towards the 

 side of the face is rather greater, much as in some Perissodactyla. 



The known genera agree with the typical Proboscidia in the posterior 

 expansion of the scapula, and its apical acumination, in the short cerv- 

 ical vertebi-se, in the flat carpal bones, in the absence of pit for round liga- 

 ment of the femur, in the flattened gi'eat trochanter, contracted condyles, and 

 Assure-like intercondylar fossa of the same bone : in the longitudinal crest 

 of the tibia separating glenoid articular faces which are on a transverse 

 line. Also in the short calcaneum, which is wider than long and tubercular 

 on the inferior face; in the five digits, the acetabulum not separated by a 

 peduncle from the iliac plates, and the lack of angular production of the 

 latter beyond the sacrum. 



Genera. — Owing to the imperfect character of the material which I 

 have had the opportunity of examining, it is not possible to state the num- 

 ber of these with absolute certainty. There are certainly three of these, 

 and probably four. So far as present knowledge goes, they pertain to one 



