310 University of California Publications in Geology [Vol. 7 



the cavity is abrupt in no. 20040 and is bordered by a sharp 

 overhanging ridge in nos. 20028 and 20049. This fossa is clearly 

 shown in Pliauchenia (Megatylopus) gigas described by Matthew 

 and Cook 2 and is strongly marked in Alticamelus. 3 There is no 

 suggestion of it in Auchenia or in Camelus. 



The lachrymal vacuities are very large and have an approxi- 

 mately triangular outline. In specimen 20028 the lachrymals 

 are separated externally from the lachrymal vacuities on one 

 side by the union of the maxillaries and frontals. In no. 20040 

 they barely touch the vacuities. 



The heavy anterior end of the zygomatic process of the 

 squamosal extends forward well beneath the posterior border oC 

 the orbit somewhat as in Auchenia, but in contrast to the form 

 in Camelus. The jugal is much thicker vertically below the 

 orbit than in ('ami lus, and exhibits a marked inferior crest or 

 ridge as described in Megatylopus gigas by Matthew and Cook. 4 



The palate is narrow (figs. 2 and 9), the long, narrow, V- 

 shaped posterior nasal opening extending forward to a point 

 slightly in advance of a line connecting the middle region of the 

 third upper molars in nos. 20028 and 20049, and to the posterior 

 end of M J in no. 20040. 



The basiphenoid and presphenoid form a deep narrow ridge 

 quite different from the inferior surface of this element in 

 Camelus and in Auchenia. The inferior processes of the ali- 

 sphenoid seem smaller, are less divergent, and do not project as 

 far inferiorly a.s in Camelus. 



The glenoid fossa is relatively narrower posteriorly than in 

 Camelus, and as in Auchenia, the outer margin of this fossa is 

 not bordered by a distinctly elevated wall or process that is seen 

 in Camelus. The postglenoid process is somewhat larger than in 

 Auchenia. 



In specimen 20028 the transverse palato-maxillary suture 

 truncates the anterior ends of the palatines rather broadly, as in 

 Camclus dromedarius. In no. 20049 the suture is more strongly 



2 Matthew, W. D., and Cook, H. H., Bull. Am. Mus, Nat. Hist., vol. 26, 

 p. 397, 1909. 



s Ibid., p. 403. 

 * Ibid., p. 398. 



