1918] Stock: The Pleistocene Fauna of Hawver Cave 



511 



smaller of the two facets for the astragalus are of nearly equal size. 

 The former facet is concave and slopes decidedly away from the in- 

 ternal channel. At the postero-inferior side of this facet the slender 

 process, present in Nothrotherium but absent in Megalonyx, has been 

 broken away. Unfortunately the large, external facet for the 

 astragalus is not complete. This surface is sigmoid in its long axis. 



Figs. 30a to 31. Nothrotherium shastense hawveri, n. subsp. Fourth and 

 fifth metatarsals, nos. 19874 and 19875, X V>. Fig. 30a, fourth metatarsal, inner 

 view; fig. 30b, fourth metatarsal, view of proximal end; fig. 31, fourth and fifth 

 metatarsals, superior view. Pleistocene of Hawver Cave, near Auburn, California. 



The fourth metatarsal , no. 19875, is but a trifle shorter than the 

 corresponding rnetapodial of Megalonyx jeffersoni. The proximal 

 end (fig. 306) is nearly quadrate in shape, though unfortunately the 

 lower portion of this extremity has been broken away in the specimen 

 from the cave. A small facet at the dorso-internal angle of the 

 proximal face, which is not represented in Megalonyx or in Hapalops 

 elongatns, forms a lateral continuation of the articulating surface 

 on metatarsal 3 for the ectocuneiform. This facet on metatarsal 4 

 is separated by a broad interarticular channel from the large facet 

 for the cuboid of the proximal end. On the inner side the surface 

 for the ectocuneiform is continuous with an articulating face for 

 metatarsal 3. The latter facet is convex anteroposteriorly, and ex- 

 tends distally along the shaft farther than does the facet for meta- 

 tarsal 5. The nearly flat facet for the cuboid is large and widens 

 ventrally, Nothrotherium differing in the latter respect from Mega- 

 lonyx. It is less extensive than in Hapalops. The facet for the cuboid 



