24 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Suborder Perissodactyla. 
Family tapiRIDAE. 
Genus ELASMOGNATHUS Gill. 
1865. Elasmognatlnis Gill, Proc. acad. nat. sci. Phila., p. 183. 
Type.— Elasmognathus hairdii Gill. 
* Elasmognathus bairdii Gill. 
1865. Elasmognathus bairdii Gill, Proc. acad. nat. sci. 
Phila., p. 183. 
1885. Elasrnognatlms hairdii True, Proc. U. 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. 14*2. 
1885. Elasmognathus dowii True, Proc. U. S. nat. mus., 
Yii (1884), p. 593. 1885. 
Type locality.— Guatemala. 
Order GLIRES.^ 
Suborder Simplicidentata. 
Family SCIURIDAE. 
1 Tullberg has recently published an elaborate work on the genera and families of 
rodents, entitled “ Ueber das System der Nagethiere, eine j)hylogenetische Stndie ” 
(Nova acta reg. soc. scient. Upsala, (iii), xviii, fasc. ir, 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, Hesperomyiclae, Arvicolidae and Muridae. 
