1913] 



Merriam: A Camel from Eancho La Brea 



315 



Lower premolar four has approximately the same relation to 

 Mj in dimensions as in Auchenia. It has a wedge-shaped cross- 

 section and approximates the form in Auchenia. There is a deep 

 enamel fold on the posterior side of the crown, as in Auchenia, 

 but the inner or medial side is an almost even vertical wall 

 without the folds seen in Auchenia. P 4 shows some evidence of 

 division of the root into two parts, and a faint groove on one 

 side may mark the line of separation. 



The upper molars all differ somewhat from those of Auchenia 

 in the less marked development of the external styles and of the 

 median ribs on the outer side of the paraconid and metaconid. 

 In M 2 the anterior lobe has a noticeably greater transverse 

 diameter than the posterior lobe. On the somewhat worn M 3 of 

 no. 20028 the meta.style is drawn out posteriorly as a wing not 

 shown in Auchenia. This wing does not appear in the unworn 

 M 3 of no. 20040. 



In Mj and M 2 the inner walls of the protoconid and hypo- 

 conid lobes tend to be a little more distinctly separated by a 

 median longitudinal groove than in Camelus. The styles and 

 inner ribs of the lower molars are less strongly developed than 

 in Auchenia. M 2 and M 3 differ markedly from the correspond- 

 ing teeth of Auchenia in the absence of the anteroexternal but- 

 tresses so characteristic of that genus. It is upon this character 

 that Wortman''' separates Camelops from Auchenia. M 3 is dis- 

 tinguished from that of Camelus by the position of the posterior 

 or third lobe. In the Rancho La Brea specimens this lobe 

 extends nearly straight back, and its inner wall is nearly even 

 with that of the anterior lobes of this tooth. In Camelus the 

 inner wall of the posterior lobe turns sharply out and away from 

 the nearly even pl^ne formed by the inner walls of the first and 

 second lobes. In Auchenia the posterior lobe of M 3 rises from 

 approximately the middle of the posterior end of the second lobe, 

 and is separated from the inner and outer walls of the second 

 lobe by a deep longitudinal groove on each side. 



« Wortman, J. L., Bull. Am. Mus. Nat. Hist., vol. 10, pp. 129-130, 1898. 



