CONDYLAETHEA. 417 



Measurements. 



Length of posterior four molars 0180 



Diameters of P-m.iv J '^°t«r°P°«*«"°^ O^f 



i transverse . 0035 



Diameters of M.i,<«°t*'™P''«^<'"<"^ ^^^ 



i transverse 0035 



Diameters of M.ii^"''*^^"!"'^*''"'"" "^t!! 



< transverse 0032 



Diameters of M.iii^''"*'"™P"^t«"'"' ^045 



( transverse 0030 



Depth of ramus atM. 1 0110 



Thickness of ramus at M. i 0060 



From the Puerco beds of Northwestern New Mexico, one specimen 

 found by D. Baldwin. 



HOPLOCONUS LINEATUS Cope. 

 American Naturalist ISH'i (May), p. 

 Plate XXV e; figs. 1-4. 



This species appears to have been more abundant than the other spe- 

 cies, Mr. Baldwin having sent me parts of fifteen individuals. Two of these 

 include parts of crania, the best preserved lacking the posterior half of the 

 brain-case and the extremity of the premaxillary only. It is somewhat 

 damaged anterior to the orbits, so that some of the foramina cannot be seen. 



In this species the predominant size of the premolars, seen in all the 

 species of this group, is restricted to the fourth in the superior series, and 

 the third and fourth below. Alveolae of two of the superior incisors are 

 preserved. The canines have a vertical position. The second premolar is 

 two-rooted. The third premolar has the posterior root wider than long, but 

 not divided into two. The fourth premolar has three roots. The crown of 

 the third is compressed so that the apex wears into a narrow anteroposterior 

 oval. The internal crest of the fourth premolar is large, and is extensively 

 visible back of the external cusp when viewed from the side. The external 

 cusps of the true molars are somewhat flattened, the posterior more so than 

 the anterior. The internal V is more open, and thus less prominent inwards 

 than in the Anisonclius sedorius. The posterior internal cusp is more prom- 

 inent and acute than in that species, and it is continuous with a posterior 

 cingulum which extends to the base of the posterior external cusp. An an- 

 terior cingulum which only extends to the base of the angle of the V. A 

 weak external cingulum on the second and third true molars; a slight one 

 27 



