24 PROCEEDINGS : BOSTON SOCIETY NATURAL HISTORY. 

 Suborder PEEISSODACTYLA. 

 Family TAPIRIDAE. 



Genus ELASMOGNATHUS Gill. 



1865. Elasmognathus GILL, Proc. acad. nat. sci. Phila., p. 183. 

 Type. Elasmognathus bairdii GILL. 



* Elasmognathus bairdii Gill. 



1865. Elasmognathus bairdii GILL, Proc. acad. nat. sci. 



Phila., p. 183. 

 1885. Elasmognathus bairdii TKUE, Proc. IT. S. nat. mus., 



vii (1884), p. 593. 1885. 

 TYPE LOCALITY. Isthmus of Panama. 



* Elasmognathus dowii Gill. 



1870. Elasmognathus dowii GILL, Amer. journ. sci. and arts, 



L, p. 142. 

 1885. Elasmognathus dowii TRUE, Proc. U. S. nat. mus., 



vii (1884), p. 593. 1885. 

 TYPE LOCALITY. Guatemala. 



Order GLIRES. 1 

 Suborder SIMPLICIDENTATA. 



Family SCIURIDAE. 



iTullberg has recently published an elaborate \vork on the genera and families of 

 rodents, entitled " Ueber das System der Nagethiere, eine phylogenetische Studie " 

 (Nova acta reg. soc. scient. Upsala, (in), xvin, fasc. n, sect. 2, 1900). In this he recog- 

 nizes as families a number of groups which are usually considered of lower rank. 

 The North American groups affected are the Cricetinae, Microtinae and Murinae, which 

 he names, respectively, Hesperomyidae, Arvicolidae and Muridae. 



