lvon] the hares and their allies 3 53 



form tooth, which, extending to the middle of the tooth and meeting 

 the reentrant angle from the external surface, divides the tooth into 

 an anterior and a posterior portion. 



In Romcrolagus there is a broad shallow infold of the enamel on 

 the external surface of the anterior half of this tooth, but the an- 

 terior and internal surfaces of this part of the tooth are smooth. 

 The main infold as in Pronolagus extends but half-way across the 

 tooth, while a corresponding reentrant angle comes in from the 

 internal surface, both angles contributing to the division of the 

 tooth into an anterior and a posterior portion. 



In Pciitalagus the first lower molariform tooth is very long. It 

 is divided by two well-marked reentrant angles, one from the internal 

 and one from the external face, into two portions, a narrower longer 

 anterior portion, and a broader shallower posterior portion. The 

 anterior portion of this tooth has two reentrant angles on its an- 

 terior face, and one each on the internal and external faces. 



In Caprolagus the anterior portion of the first lower molariform 

 tooth is separated from the posterior portion by a single reentrant 

 angle from the external surface. The anterior portion considerably 

 exceeds in size the posterior portion ; it has two narrow reentrant 

 angles on its anterior face, a broad shallow one on the external face, 

 and a similar one on the internal face. (Major '99, pi. 37, fig. 23.) 



The reentrant angle of the second, third, fourth, and fifth upper 

 molariform teeth of Bracliylagiis extends but half-way across the 

 tooth ; it is not crenated. 



The second upper molariform tooth of Nesolagiis has a short 

 non-crenated reentrant angle extending about a third the distance 

 across the tooth (Major '99, pi. 37, fig. 17). Probably the third, 

 fourth, and fifth upper molariform teeth are similar. 



In Pronolagus the reentrant angle of the second, third, fourth, and 

 fifth upper molariform teeth extends nearly all the way across the 

 tooth and is crenated. The internal half of the angle is rather wide 

 and open. 



In Pciitahgus the reentrant angle of the second, third, fourth, 

 and fifth upper molariform teeth extends completely across the 

 tooth. The crenation of its sides is more marked than it is in any 

 other genus of Leporidie. The sides of the angle are almost in 

 contact throughout their entire extent. 



In Romcrolagus the crenated reentrant angle of the second, third, 

 fourth, and fifth upper molariform teeth does not extend quite 

 50 far across the tooth as it does in Proiiolai/us, but at the same 



