24 PROCEEDINGS : BOSTON SOCIETY NATURAL HISTORY. 

 Suborder Perissodactyla. 

 Family TAPIRIDAE. 



Genus ELASMOGNATHUS Gill. 



1865. Elasmognathus Gill, Proc. acad. nat. sci. Pliila.,p. 183. 

 T}^e. — Elasmognathtis hairdli Gill. 



* Elasmognathus bairdii Gill. 



18G5. Elasmognathus bairdii Gill, Proc. acad. nat. sci. 



Phila., p. 183. 

 1885. ElasmognutJtus bairdii Teue, Proc. XJ. 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. Elasmognathics dowii True, Proc. U. S. nat. mus., 



Yii (1884), p. 593. 1885. 

 Type locality. — Guatemala. 



Order GLIRES.^ 

 Suborder Simplicidextata. 



Family SCIURIDAE. 



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

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

 (Nova acta reg. soc. scient. Upsala, (iii), xviii, fasc. ii, 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 Cricetinac, Microtinae and Murinae, which 

 he names, respectively, Hesperomyidae, Arvicolidae and Muridae. 



