Vol. 5] Furlong. — An Aplodont Rodent from Nevada. 403 



and in the median line only. From a slight depression anterior 

 to the dental series, they extend laterally on a nearly horizontal 

 plane to the infraorbital foramina. The Recent species differ in 

 this respect in that the mamillaries slope upward more sharply 

 from the median line. 



GENEKTC POSITIONS AND AFFINITIES. 



A. ale.randrae represents an advanced stage of development " 

 between Meniscomys and Aplodontia. It shows a distinct likeness 

 to both genera, and is probably near the direct line of descent 

 leading toward Aplodontia. The genus Mylagaulodon Sinclair 

 shows affinity to A. ale.randrae through Meniscomys. It is 

 probably an aberrant form of the Aplodontidae as was recently 

 suggested by Matthew and Gidley. 5 



5 Op. cit. 



Issued March 31, 1910. 



