LEPUS 



233 



superior border of the malar, when the latter is measured from 

 the anterior end of the squamoso-malar suture to the antero- 

 inferior angle of the orbit. 



The external auditory meati are prolonged upwards and 

 backwards into tubular structures, which, combined with the 

 bullae, resemble flasks. 



The angular and condyloid processes of the mandibles are 

 much developed ; the coronoid processes nearly absent. The 

 mental foramina are small, and lie well in front of the cheek-teeth. 



There are thirty teeth at birth ; soon afterwards a pair of 

 upper incisors is lost, and a little later the three anterior upper 

 and the two anterior lower cheek-teeth are shed and are re- 

 placed by their permanent successors. Thus the adult dentition 

 comprises twenty-eight teeth, of which the arrangement is — 



.2-2 



pm 



3-3 



28. 



The large upper incisors have each a groove, often filled with 

 cement, running vertically along their anterior surfaces. (Fig. 34, 

 p. 175.) The courses of their roots are plainly visible externally. 



ant. 



ant. 



ext^- 



inf- 



tnf- 



exf- 



post. post. 



Upper. Lower. 



Fig. 46. — Cheek-Teeth of Lepus^ diagrammatic and magnified. 



The permanent cheek-teeth are without roots, so that they 

 grow throughout life. They have the appearance of cylinders, 



VOL. H. Q 



