158 THE SKULL. [chap. 



to the under surface of the zygomatic process of the 

 squamosal to form the outer side of the glenoid articular 

 surface. In the spotted Cavy (Cculogenys), the zygoma has 

 an enormous vertical expansion, with a rugose or pitted outer 

 surface, and a large fossa in the inner side of the maxillary 

 portion, with which the cavity of the mouth communicates 

 in the recent state. 



The lachrymal bone usually presents both orbital and 

 facial surfaces, but the orifice of the canal (lachrymal 

 foramen) is always well within the margin of the orbit. In 

 the Beaver, and many others, the facial portion is reduced 

 to a mere tubercle, and in the Hare the lachrymal is entirely 

 within the orbit. 



The palate of the Rodents is usually narrow. In the long 

 space intervening between the incisor and molar teeth, it 

 has no definite lateral margins, but rounds off insensibly 

 on to the sides of the face. In this region the anterior 

 palatine foramina form very conspicuous longitudinal slits, of 

 specially large size in the Hares. The portion of the palate 

 situated between the molar teeth is often very narrow 

 anteriorly, and ends posteriorly in a thickened excavated 

 border. In the Hare it is reduced to a short transverse 

 bridge, extending across the middle line between the pre- 

 molar teeth. In the Capybara and Guinea Pig the alveolar 

 border of the maxilla is very long, and presents the remark- 

 able peculiarity of extending backwards beneath the orbit 

 to unite with the squamosal at a level with the anterior 

 border of the glenoid fossa. It thus forms the outer border 

 of a large conical cavity, opening posteriorly, bounded on 

 the inner side by the pterygoids, above by the alisphenoids, 

 and below by the palatines. 



The pterygoids are always simple subquadrate lamellae, 

 early ankylosed with the basisphenoids, often sending a 



