lyon] the hares and their allies 403 



The interparietal is present as a distinct bone in Oryctolagits. 



The bony palate is relatively long. The horizontal plate of the 

 palate bone well developed. It enters into the formation of the bony 

 palate to a greater extent than it does in Lcpns, where it forms a 

 fourth to a third of the bony palate, and to a less extent than it does in 

 Roiiicrolagits where it is about half of the bony palate. The portion 

 of the palate bone that borders the maxilla caudad of the posterior 

 edge of the bony palate is moderately developed and thus helps to 

 form part of the roof of the mouth along the posterior dental alveoli. 

 The distance between the vertical plates of the palate bones, that is 

 the width of the choanse, is very slight, less than it is in any other 

 genus. The pharyngeal vault is high. The length of the bony 

 palate, measured midway between the median line and the inner edge 

 of the dental alveoli, is about equal to the greatest width of the 

 incisive foramina, which are narrow in this genus, and it is much 

 greater than the least distance between the two vertical plates of the 

 palate bones. 



The posterior palatine foramina are of moderate size and situated 

 in the usual position at the anterior outer angles of the horizontal 

 plates of the palate bones. 



The anterior portion of the zygoma is deep, as it is in Lcpns, but 

 the under edge of the posterior portion is cut away, rendering it 

 shallower. The antero-inferior angle of the zygoma is enlarged and 

 flares outward to a rather marked extent. The foot-like extremity 

 of the zygomatic process of the squamosal is enlarged. The lateral 

 length of the squamoso-malar suture is contained between one and 

 one and a half times in the superior border of the malar, measured 

 from the anterior edge of that suture to the antero-inferior angle of 

 the orbit. The posterior free extremity of the malar is long. 



The audital bullae, the fenestration of the maxillse, and the shape 

 of the mandible in Oryctolagus show nothing distinctive of the genus, 

 and may be said to represent normal degrees of development. 



Teeth (pi. xci, 5; figure 44, 22). — First upper incisors, with 

 longitudinal groove on anterior face, always simple, moderately 

 shallow and unfilled with cement. First upper maxillary tooth has 

 typical folding of enamel on the anterior surface, a deep median 

 reentrant angle, on either side of which is a smaller reentrant angle. 

 The first lower molariform tooth has a small reentrant angle on its 

 anterior face, and a shallow broader reentrant angle on the external 

 surface of the anterior half of the tooth which is separated from the 

 posterior half by a single reentrant angle. The second, third, fourth, 

 and fifth upper molariform teeth show each a deep reentrant angle 



