408 THE PUERCO EPOCH. 



specimens. The posterior two cusps are well developed, and soon connect 



on attrition, and the external sends a long point forwards and outwards. 



The third molar has an elongate heel, and internal and external median 



cusps, of wliich the latter is crescentic in section. The ramus is compressed, 



and becomes shallow anteriorly. 



The superior molar has the characters of those of H. kowalevskianuSy 



the external wall being lost. 



Measurements. 



Lenpth of posterior six inferior molars (No. 1) 036 



Length of base of Pm. ii (No. 2) 003& 



T%- .. „ -D-, ■■■< anteroposterior (No. 1) 007 



Diameters Pm. iii ^ ' ,v \x nni 



< transverse (No. 1) w-i 



Diameters Pm. iv 5 anteroposterior (No. 3) 0008 



( transverse (No. 3) 0045 



Diameters M.ii^''°'«^°P°«»«':j°^(f°-^) °^ 



I transverse (No. 1) OOo 



T^. . ■., .-•< anteroposterior (No. 1) 00C6 



Di.imeters M. Ill ^ ' .»t ,n nm 



t transverse (No. 1) 0U4 



Depth of ramus at Pm. iii (No. 1) 008 



Depth of ramus at M. ii (No. 1) OU 



Besides the difference in the relations of the inferior premolars above 

 cited, this species differs from the H. Jiowakvskianus in its superior size. 



The jaws described were found by Mr. D. Baldwin in the Puerco bed& 

 on the Rio San Juan, New Mexico. 



ANISONCHUS Cope. 



Paleontological Bulletin, No. 33, p. 488, Sept. 30, 1881. Proceedings American Philosophical Society, 



1881, p. 488. 



This genus is only known from dental characters, and only the molar 



teeth have been preserved. These are Pm. -r-; M. -. The first superior 

 '^ 4 3 



premolar is unknown. The third and fourth consist of an external conic 

 cusp, and an internal elevated crest or lobe, as in Periptychus. Molars sup- 

 porting two external tubercles, an internal V, and a posterior internal cusp 

 cut off from the internal V. The limbs of the V represent the intermediate 

 tubercles of Periptychus and other genera, and the apex of the V represents 

 the internal median tubercle of that genus The posterior internal cusp 

 is separated from it by a vertical groove on the inner face of the crown,, 

 and is continuous with a posterior cingulum of the crown. 



