1913] 



Stock : 



Nothrotherium and Megalonyx 



351 



in 1903. Miller 1 - lists the following vertebrates from the Upper 



San Pedro Pleistocene : 



Mammals — Birds — 



Equus Aeehmophorus, n. sp. 



Bison 

 Camelid 



Nettion carolinense (Gmelin) 

 Sturnella neglecta Audubon 



The specimen, no. 19720, shown in figures 9, 10, and 11, is 

 very long and narrow, differing greatly in this respect from the 

 shorter and stouter second phalanges of Mylodon and Megalonyx. 



10 



11 



Figs. 9, 10, and 11. Nothrotherium ( ?), sp. Second phalanx, no. 19720, 

 X %. Upper San Pedro Beds, San Pedro, California. Fig. 9, superior 

 view; fig. 10, view of proximal face; fig. 11, lateral view. 



The median groove of the distal trochlea is of the broad and 

 rather shallow type as in Mylodon, differing in this respect from 

 Megalonyx. The depression at the end of the groove on both 

 the dorsal and ventral surfaces is broad, and is deepest on the 

 ventral surface. The condyles, unequal in size, are more 

 definitely constricted off from the rest of the shaft than in 

 Megalonyx, and have their postero-dorsal muscle ridges but little 

 developed. The two lateral facets of the proximal end are 

 divided by a thick median ridge, which widens superiorly and 

 inferiorly. Below this expansion the shaft is grooved for a 

 short distance on its inferior surface. 



12 Miller, L. H., Contributions to Avian Palaeontology from the Pacific 

 Coast of North America, Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, p. 

 115, 1912. 



