364 University of California Publications in Geology [Vol. 12 



but the first premolar is small, and the form is evidently of different 

 proportions. Compared to C. dromedarins the maxillary-premaxillary 

 portions of the fossil are seen to be proportionately more elongate than 

 in the living species, the first upper and lower premolars are much 

 heavier than the lower canine, and the outer incisors are more robust. 



In resume, the dentition of the new specimen cannot be referred 

 to the genera Alticamelus, Auchenia, or Camelops. The general dental 

 formula and arrangement in front of the cheek tooth series suggests 

 Pliauchenia or Camelus, but in their development the anterior teeth 

 differ from those of both genera. The specimen represents a giant 

 specialized form that might have been derived from ancestral stock 

 resembling Pliauchenia spatula. 



Limb elements. — The scaphoid and lunar are broader transversely, 

 deeper anteroposteriorly and narrower dorsoventrally than the corre- 

 sponding bones of Camelops, giving the broad and flattened carpus 

 increased strength. The tarsus (pi. 47 and fig. 2) differs more from the 

 Rancho La Brea type than does the carpus, the cuboid being broader 

 transversely and much shallower dorsoventrally, while the navicular 

 is both broader transversely and deeper dorsoventrally. The general 

 form of the cuboid is, however, nearer that of Camelops than that of 

 the llama, the calcaneal groove of the anterodorsal surface and the 

 deep gutter diagonally crossing the outer side being deep and promi- 

 nent, instead of relatively inconspicuous as in the llama. The foot 

 bones are well represented (figs, llor-llc). The writer has referred 

 the longer phalanges of Pliauchenia merriami to the manus and the 

 shorter to the pes, as in the genus Camelops. In Auchenia the bones 

 of the manus are slightly heavier and shorter than those of the pes, 

 but this form has been seen to be farther removed from the Eden type 

 than is the Rancho La Brea. The accompanying table shows com- 

 parative measurements of the foot of the large Eden forms with those 

 of Camelops hesternus, Pliauchenia gigas, and Alticamelus procerus. 

 The first phalanx of the manus in the present form exceeds in length 

 that of the large Pliauchenia of the Snake Creek, while it is of equal 

 length with Camelops, in which the pes is, however, longer. 



