THE MAMMALIA OF THE UIXTA KOIIMATIOX, 481 



nent and but little recurved. The position of the spine is somewhat different from 

 that seen in the recent selenodonts, in which the spine is phiced in advance of the 

 median line, thus making the prescapidar fossa much smaller than the postscapular. 

 This inequality is also shown in a less degree in Zieptotroyulns, in which respect this 

 genus agrees with the earlier selenodonts, such as Anojjloihermm and Oreodon. 



Of the humerus we have only the distal end, which, however, shows some inter- 

 esting characters. The internal epicondyle is not pi-orainent and is pushed to the pos- 

 terior side ; the inner condyle of the trochlea is much extended transveiscly, while 

 the outer condyle is narrow; the intercondylar ridge is not prominent, and is above 

 rounded and rather broad, but rapidly becomes narrow and sharp. This portion of 

 the humerus forms a sti'ong contrast to that of the oreodonts, v/hich finds a parallel 

 onlj' in AnopIoVierium. Tlie anconeal fossa is deep and nariow and appears to per- 

 forate the shaft. 



The ulna and radius are very closely applied together, but they do not coalesce, 

 at least in the proximal portion, whatever may be true of the distal end. The ulna 

 has a heavy and prominent olecranon and a deeply incised sigmoid notch, with a re- 

 curved superior margin. The contact with the humeral condyles is limited to very 

 small inner and outer facets, which are but continuations backwards of the corre- 

 sponding radial facets. The shaft is quite broad at the level of the head of the radius, 

 but rapidly tapers below this point and becomes very slender and reduced. The 

 head of the radius is both broad and deep ; it is only slightly concave, and the division 

 into facets only obscurely marked ; the anterior margin rises somewhat towards the 

 inner side ; the groove for the intercondylar ridge is very shallow, and the front margin 

 is not notched. Below the head, the shaft tapers and becomes more rounded. Un- 

 fortunately neither the distal ends of the forearm bones, nor any of the carpal ele- 

 ments, have been found. 



The femur is represented by a much damaged pioximal end, which, however, 

 presents some interesting features. The head is small, hemispherical, and set upon 

 a long and very distinct neck; the pit for the lie/amentum teres is but faintly marked. 

 The great trochanter is broken away, but it was obviously large and, with 

 the strongly projecting neck, makes this region of the bone unusually broad. The 

 second trochanter is large, rugose and prominent; what appears to be the remains of 

 a ridge, connects this trochanter with the greater one, as in Ili/ojtuUnnus, to the femur 

 of which this fragment bears considerable resemblance. The shaft is broad and flat- 

 tened alx)ve, but appears to taper rapidly and to become more rounded below. 



Of the tibia we have only the distal end, with fragments of the proximal con- 

 dyles, which, however, are too much injured for description. The lower portion of 



