63 THE MAMMALIA OF THE DEEP RIVER BEDS. 



animal. The anterior nares are higher, more oval in shape and more inclined hack- 

 ward than in Temnocyon corypJiceus, less so than in Canis latrans. In the former 

 they are small, nearly circular in shape and vertical in position. The horizontal por- 

 tion of the premaxillas is shorter, less massive and rounded than in the coyote, in 

 correlation with the smaller incisors, and at the symphysis the two are less closely 

 applied. The ascending portion is also quite differently shaped ; it is much longer, 

 broader and more steeply inclined, and its superior and anterior borders pass into each 

 other almost imperceptibly, while in the coyote the two meet at an angle not very 

 much greater than a right angle. The palatal portion differs but little from that seen 

 in the latter species, but the incisive foramina are somewhat more anterior in position 

 and encroach less upon the maxillaries. 



The maxillary, in its extension upon the face, is short, but relatively deep verti- 

 cally, and this height rapidly increases backward, so that the premaxillary suture is 

 steeply inclined. The canine alveoli cause more marked prominences upon the face 

 than in Canis latrans, and the muzzle is more constricted behind them. The infra- 

 orbital foramen is nearer to the orbit than in that species, but occupies the same 

 position with reference to the teeth, opening above the interval between p_3 and iM. 

 The palatal processes are somewhat narrower than in the coyote, and the suture 

 between them is marked by a low rugose ridge. The palatines have a less extent, 

 both in length and breadth, than in the modern form, their anterior borders, which in 

 the latter reach to the interval between pJ} and M, hardly extending beyond the mid- 

 dle of the sectorial. On the other hand, the front margin of the posterior nares is 

 quite behind the molar alveoli, while in the coyote it is opposite the front of m^ • 

 the palatal notches are also much less deeply marked than in the latter. The pos- 

 terior nares are long and narrow and somewhat constricted in the middle of their 

 course ; the pterygoids have larger hamular processes than in the coyote and the 

 pterygoid fossae are better marked. 



The mandible differs in important respects from that of Canis latrans. The hori- 

 zontal ramus is shorter, but deeper and thicker; the chin rises more steeply, which 

 produces less procumbency in the incisors ; the lower border is more sinuously 

 curved, descending more abruptly from beneath the coronoid, and the angular hook 

 longer and stouter. The ascending ramus has a greater antero-posterior extent, and 

 the coronoid is broader, more inclined backward, and with more curved posterior 

 margin ; its anterior border is wider and more distinctly defined and displays a 

 groove for the attachment of the buccinator and maxillo-labial muscles, which would 

 seem to indicate that these muscles were better developed than in the existing form. 

 This broad anterior surface is reflected over upon the upper border, where it forms a 



