1921] FricJc: Faunas of Bautista Creek and San Timoteo Canon 349 



Edentata 



Two specimens from the Eden, which according to Dr. Stock have 

 undoubted megalonychid and possibly nothrothere characters, are 

 of great interest, suggesting the earliest known occurrence of the two 

 genera in North America. Both Nothrotheriuni and Megalonyx are of 

 frequent occurrence in the California Pleistocene, but neither have 

 heretofore been recognized in North America in so early a formation 

 as the mid-Pliocene. A genus, Pronothrotlierium, has been described 



56a 



Figs. 56<z-56c, 57a-57c. Nothrotherium? or Pronothrotherium?, sp. Edentate 

 cheek teeth, X 1. Figs. 56a to 56e, no. 23374; figs. 5'7a to 57c, Megalonyx?, sp., 

 no. 23371. Eden beds, California. 



from the Pliocene of South America, and Megalonyx leptostomus 

 Cope from the Blanco Pliocene of Texas. The present collection from 

 the overlying San Timoteo also includes a tooth of Megalonyx type, as 

 shown above. 



NOTHROTHERIUM? or PRONOTHEOTHERIUM?, sp. 



Material.— K cheek-tooth, Univ. Calif. Coll. Vert. Pal. no. 23374 (figs. 56a- 

 56c), Univ. Calif, loc. 3269'. 



Description. — Though one side of the triturating surface is dam- 

 aged the unbroken walls of the tooth (fig. 56c) show the transverse 

 diameter of the crown to have been under twice that of its antero- 

 posterior diameter. The triturating surface is deeply concave, its 

 transverse crests being furnished with beveled edges. A medium 

 vertical groove on both the outer and inner surfaces tends to divide 



