506 



University of California Publications in Geology [ VoL - 10 



surface is sigmoid in dorso-ventral direction toward the external 

 side. Internally this surface is flatter. The distal end bears a heavy 

 carina with an offset along the lower portion of the inner side. 



Measurements of Second Metacarpal, no. 19872 



Total length a89 mm. 



Depth of distal carina 43.4 



Greatest width of distal end 27.6 



a, approximate. 



Figs. 26a and 26b. Nothrotherium shastense hawveri, n. subsp. Third meta- 

 carpal (?) , no. 19861, X V-2- Fig. 26a, lateral view; fig. 26b, view of distal end. 

 Pleistocene of Hawver Cave, near Auburn, California. 



The distal portion of a metapodial (figs. 26«, 266), no. 19861, from 

 Hawver Cave resembles most closely the corresponding part of the 

 median metacarpal of Nothrotherium. The shaft at the middle is 

 nearly square in section, and is more slender than that of the corre- 

 sponding metapodial of Megalonyx or of Hapalops. Its distal end 

 is also not so large as that in the latter genus. The carina is nearly 

 straight, thus differing somewhat from that in either the Miocene 

 form or in Megalonyx. Articulating offsets are present along the 

 lower half of each side of the distal carina. 



Measurements of Metapodial, no. 19861 



Greatest depth of distal end 45.8 mm. 



Width of distal end 31 



Contrasted with the tibia of Megalonyx, the specimen from Haw- 

 ver Cave, no. 19965, is smaller but similar in general shape. As in 

 the former genus and also as in Hapalops the proximal and distal 

 extremities are much expanded, particularly the proximal end. The 

 proximal half of the shaft below the articulating surface differs from 

 that of Hapalops in being flatter and not as thick anteroposteriorly. 

 This is distinctly seen in end view where in the tibia of Hapalops the 

 anterior tuberosity is very prominent. Scott describes the proximal 

 portion of the shaft of the tibia in H. longiceps as being trihedral 

 in shape. In Nothrotherium it would appear that the portion of 



