928 THE JOHN DAY FAUNA. 



M. 



Probable length of pelvis l'^2 



Length of ilium (inferential) 037 



Anteroposterior width of ilium at base 013 



Anteroposterior diameter of acetabulum 013 



Depth of pelvis at ischiapubic symphysis 018 



Width of obturator foramen Oil 



The fragment of lower jaw above mentioned was the specimen from 

 which the existence of this species was originally inferred. Its characters 

 are as follows : 



The mandibular ramus is robust and shallow, and quite distinct from 

 the deep jaw of A. hartshornianus. The sectorial has perhaps twice the bulk 

 of those of the G. lippincottianus and A. cuspigerus. From that of the latter 

 it differs further in the small inner tubercle and contracted heel. 



The sectorial part of the tooth is relatively small, not exceeding the 

 heel in length, and its cusps are low. The heel is notable for the elevation 

 of the tubercle of the inner side, which exceeds that of the outer ; the latter 

 also is contracted, standing within the external base, which is represented 

 by a short cingulum. A weak cingulum below the sectorial blades. Sur- 

 face of the enamel rugose where not exposed to friction. 



Measurements. 



M. 



f vertical, anterior cusp 006 



I vertical, heel 0038 



Diameters of sectorial jj^j^^gj.j,p„gjgri„^ 0115 



1 transverse, middle 006 



Depth of ramus at sectorial 012 



Thickness of ramus at sectorial 007 



The third specimen, a cranium, already mentioned, displays the base 

 of the skull more distinctly than any other. The condyloid foramina are 

 seen to be close to the / /. postica, and the / caroticus is not externally 

 distinguished from the latter. The / alisphenoidale posticum is small, and is 

 wiell in advance of the large / ovale. The / a. anticum is within ihe / rotun- 

 dum. The latter is large and distinct from the / sphenoorbltale. The post- 

 glenoid is rather large. The meatus auditorius externus is a sub vertical oval; 

 has no slit-like enlargement, nor a recurved lip. The palatine foramina are 

 opposite the inner border of the first tubercular molar. A shallow groove 

 extends anteriorly from each for a considerable distance. The maxillo- 

 palatine suture crosses the middle line of the palate opj^osite the anterior 

 border of the sectorial. The frontal sends a long process anteriorly on each 



