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University of California Publications in Geology [Vol. 10 



is separated from the large lateral facet for metatarsal 5 by a right 

 angle. In Hapalops this angle is acute. 



The shaft is well rounded internally, but the outer side is flat- 

 tened more than in the fourth metatarsal of Hapalops. The distal 

 extremity is greatly expanded dorsoventrally, but the carina is much 

 less developed than in either Megalonyx or in the Miocene genus. 

 The latter is bordered along the inner, lower half by an articulating 

 offset. The dorso-external border of the metapodial ends distally 

 in a large tuberosity which surmounts the carina. A small facet for 

 a sesamoid is located at the ventral and external side of the carina. 



A fragmentary fifth metatarsal, no. 19874 (fig. 31), was associated 

 with the fourth metatarsal. The inner side of this specimen is flat- 

 tened and sharply separated from the dorsal surface. At the proximal 

 end of the inner surface is a rather large facet for the adjacent meta- 

 podial. A remnant of the articulating surface for the cuboid remains 

 and is separated from the inner facet by a right angle. The distal 

 end is tuberous and bears a small but distinct facet for the rudimen- 

 tary toe. Unfortunately the entire lateral process has been broken 

 away. The metapodial was, however, more expanded in this direction 

 than that of Megalonyx, in which respect Nothrothcrium is more like 

 Hapalops. 



32b 32a 32c 



Figs. 32a, 32b, and 32c. Nothrotherium shastense hawveri, n. subsp. Ungual, 

 digit 3, pes, no. 19889, X Vj- Fig. 32n, lateral view; fig. 326, inferior view; 

 fig. 32e, superior view. Pleistocene of Hawver Cave, near Auburn, California. 



