52 



MICROTINiE 



of a posterior loop, followed by from three to seven sub- 

 stantially closed alternating triangles, and terminated by 

 an anterior loop of crescentic shape formed chiefly by the 



Fig. 24. — Pitymys planiceps Miller. 



Dorsal, ventral, and lateral views of skull, enlarged ; the small figure shows 

 the skull in dorsal view, natural size (B.M., No. 10.7.7.219, type and 

 only known specimen). 



fifth and sixth inner salient angles ; in young stages of wear the 

 outer side of the anterior loop shows some minute and quite 

 ephemeral complications. The interest of this tooth in Phena- 

 comys lies in the unusual variability which it displays, from 



I 



