THE MAMMALIA OF THE DEEP RIVER BEDS. 



67 



some differences in the disposition of the foramina in its neighborhood ; thus, the 

 foramen lacerum posterius extends less around the hinder end of the bulla and is 

 confined to its postero-internal angle, running almost parallel to the basicranial axis. 

 Still more important is the fact that the anterior lip of the auditory meatus, extend- 

 ing along the post glenoid process, overlaps and conceals the glenoid foramen. In- 

 deed, I cannot altogether satisfy myself that the foramen is present at all; but there 

 is a long, narrow and curved slit between the lip and the process, which probably 

 contains the entrance to the foramen. In Temnocyon coryphaeus the foramen occupies 

 the position of the slit just mentioned, but is much more conspicuous, resembling 

 the same structure in the raccoon. 



The zygomatic arches are relatively longer and more massive than in Canis ; 

 they arch outward as far, but much less strongly upward, and thus, when seen from 

 the side, pursue a straighter course. The root of the zygomatic process of the 

 squamosal is continued backward as a broad shelf over the mastoid process, as is 

 also the case in Temnocyon coryphaeus though not in Canis. The glenoid cavity is 

 more extended transversely than in the latter, and is more concave, the hinder margin 

 being elevated into a ridge, which rises gradually into the postglenoid process, which 

 is longer and more curved anteriorly than in the coyote. The jugal is very long and 

 extends backward to the outer angle of the glenoid cavity ; the masseter ridge is 

 more prominent and rugose, and the masseter surface wider than in the recent 

 animal ; the postorbital angle, which is but slightly developed in the latter, does not 

 appear at all. The anterior end of the jugal is bifurcate and the inferior branch 

 descends lower upon the molar alveolus than in the coyote. The lachrymal has about 

 the same extent upon the face as in that species, but possesses a spine in the form of 

 an obtuse ridge ; the foramen is single and placed entirely within the orbit. 



The specimen does not permit ns to determine the share taken by the front als in 

 forming the roof of the cranium, but they possess considerable extension upon the 

 face. The supraciliary ridges are well marked and rugose and converge rapidly to 

 form the sagittal crest; clearly, no lyrate "sagittal area" could have been present. 

 The forehead is not so flattened as in Temnocyon, but slightly arched from side to 

 side, and the postorbital processes are hardly more developed than in that form and 

 consequently much less so than in Canis lairans. The nasal processes are very long 

 and nearly reach the premaxillaries, though in this respect there is some asymmetry 

 in the specimen, the process on the left side being appreciably longer than that on 

 the right. Small frontal sinuses are present. The nasals are relatively long, and are 

 broader and more convex from side to side than in the coyote ; the anterior border is 

 not emarginate, but obliquely truncate and considerably longer than in the recent 



