§76 THE WHITE EIVER FAUNA. 



ward as the posterior border of the second mohir. From this point the 

 a,nterior suture extends to the posterior border of the third molar. The 

 palatal notch is rectangular and is not wider than the palatine bone on each 

 side of it. 



The last superior molar in this species is not grooved, has a round 

 section, and is smaller than the first molar. The first is also small, and 

 has a deep groove on its anterior face. Of the intermediate four molars the 

 two median are the largest. The crowns of the molars, except the first, are 

 without enamel on the external side, and in the last there is no enamel on 

 the posterior side also. The inner side of the four intermediate molars is 

 deeply grooved for a short distance, which gives a fissure-like notch on attri- 

 tion. This disappears after use, as does also a less profound crescentic fossa 

 in the middle of the crown, whose concavity is directed outwards. A line 

 connecting the external borders of the molars is strongly convex; that con- 

 necting the interior borders but slightly convex. The supex-ior incisors 

 <3escribe a short arc, their triturating surfaces being directed exactly down- 

 wards. The groove of their anterior face divides the latter equally. The 

 inner division is more prominent than the outer. 



The mandible is contracted forwards, and the inferior outline rises 

 gradually to the short symphysis. The symphyseal articular surface is 

 oval. The ascending ramus rises abruptly opposite the middle of the last 

 molar. Its anterior face at the base is nearly transverse, owing to the sharp 

 prominence of the corresponding inner boi'der of the ascending ramus. In 

 not one of my specimens is the angular portion of the jaw preserved. The 

 condyle is subglobular in front, with a narrow posterior prolongation, as in 

 the Lepus sylvaticus. The masseteric muscular insertion is flat and has a 

 regularly convex anterior border, which does not extend beyond the line of 

 the posterior border of the penultimate molar. There are two mental fora- 

 mina, one on the middle of the depth of the ramus, below the fissure between 

 the second and third molars ; and the other, marking the posterior third of 

 the diastema, near its superior border. The pterygoid fossa of the ramus is 

 deep, and its anterior border is well defined ; its anterior border is pierced 

 opposite the middle of the vertical diameter of the ramus for the dental 

 artery and nerve. The alveolus of the inferior incisor is marked by a Ion- 



