354 University of California Publications in Geology [Vol.7 



of the inner face extends farther inferiorly. The groove between 

 the two distal condyles widens inferiorly. 



14 



Figs. 13 and 14. Megalonyx calif ornicus, n. sp. Third digit of left 

 anterior limb( ?), no. 20002, X %. Rancho La Brea Beds. Fig. 13, lateral 

 view; fig. 14, superior view. 



The second phalanx is heavier than in M. jeffersonii. The 

 median ridge of the proximal articular face is thick and widens 

 inferiorly, forming a slight protuberance below the inner facet. 

 The postero-dorsal ligamental ridges of the distal condyles are 

 very pronounced. 



The osseous sheath on the inner side of the ungual phalanx 

 has been broken away. The upper portion of the proximal 

 articular face differs from M. jeffersonii in that the outer side 

 is produced backward farther than the inner side. 



The tentative position of this digit is based upon Leidy's 

 statement that in the first phalanges of the front foot "the 

 proximal or metacarpal articulation is a deep, vertical concavity, 

 extending from top to bottom of the bone, with an offset on each 

 side inferiorly in the median phalanx, but on one side only in 



