1919] Merriam: Tertiary Mammalian Faunas of Mohave Desert 541 



AELUEODON or TEPHROCYON, sp. D 



An interesting specimen, no. 22320, from locality 2733, in the lower 

 portion of the Ricardo formation includes fragments of the skull 

 with a portion of the dentition including the upper carnassial, P.,, P 4 , 

 and the heel of M t . The upper carnassial is of the typical Aelurodon 

 type with large, sharply separated protostyle. It represents a form 

 smaller than the hetter known Aelurodon forms, the animal having 

 approximately the dimensions of the average specimens of Tephrocyon. 

 The lower premolars (fig. 139c) are heavy, thick transversely, and 

 with well developed cingulum. P 2 has a prominent posterior cusp 

 with small but well marked anterior and posterior basal tubercles. 

 P 4 has a prominent posterior cusp with well marked anterior and 

 posterior basal tubercles. The heel of M t (fig. 139(f) shows the hypo- 

 conid and entoconid of approximately the same size. Both tubercles 

 are low, and the heel has distinctly a crushing function. 



This specimen may represent a type of animal known in other 

 material from this region and referred to Aelurodon in the descriptions 

 above. 



LIMB ELEMENTS 



A number of limb elements representing canid forms from the 

 Ricardo beds are presumably to be referred to some of the species 

 described above from jaws and teeth. 



Two very large specimens, nos. 21312 and 22509 (figs. 149, 150), 

 possibly represent Aelurodon? aphobus. A smaller specimen, no. 

 21497 (fig. 151), is possibly the undescribed form Aelurodon, n. sp A. 



The distal end of a femur no. 21314 may represent an Aelurodon 

 or Tephrocyon species. 



In specimen no. 22321 (figs. 140a to 143), found associated with 

 parts of a skull and dentition, no. 22320, at locality 2733, there is 

 represented a considerable portion of a foot with short, rather heavy, 

 strongly curved, cat-like metacarpals. In this specimen the proximal 

 end of metacarpal III shows characters not unlike those of specimen 

 no. 22289 from the Cedar Mountain Miocene of Nevada. Only a 

 proximal end is preserved. The facet for articulation with the 

 magnum is not as deeply curved as in the puma, but the median prox- 

 imal facet for articulation with metacarpal II is raised relatively high, 

 and has nearly the same position as this facet in the puma. This 



