<)1'8 MO.NOdKAI'IlH Ol' NOUTII AMKIMOAN UODIJMTIA. 



Genuh colon YMYS Marsh. 



CiilimomyH Maicmii Aincr. Journ. Hci. niiil ArtH, 'M »er. iv, 187'^, 'i'iO. 



Known only from Hcvpral isolated molar toctli of an appan^ntly Sciuriiio 



character. 



COLONYMYS CELEIt Mar^li. 



Coloitomiji ctler Maiinii, Aiiicr. .lourn. Scl. Aud Arts, 3d ler. Iv, 1H72, 990. ,^ 



Aiioiit half the size of the Brown Rat {Mus decumanus). Known, like 

 the i,'('nns, only from a low detached tiiolur teeth, from the Tertiary dejjosits 

 of Henry's F< k, Wyoming. 



Genus TAXYMYS Marsh. 



Taxjpn'jn Maiihii, Amor. Jonni. Sci. nnd Artx, M hot. iv, \HTi, 21!). 



Apparently allied to the trne S(inirrels, hut too imperfectly known to 

 admit of characterization. 



TAXYMYS LUCARIS Marsh. 



Taxjimija hicaria Mauhh, Amer. Journ. Sci. nnd Arts, 3d «er. iv, 1879, 919. 



Kather smaller than the Flying S(iuirrel {Sciurojiterus volucella). Dc- 

 scrihed from a portion of an upper jaw, with the first two molars in place, 

 and from a vcrtehra supposed to l)elong to the same animal. First upper 

 premolar very small, as in the Arhoreal, Flying, and Ground Squirrels, with 

 a similar contijrmation of the triturating surface. From Tertiary deposits, 

 Henry's Fork, Wyoming. 



Genus TILLOMYS Marsh. 



TilloHiya MAnsn, Amer. Journ. Sci. and Arta, 3d ser. iv, 1879, 910. 



Two species, dilFering mainly in size, are referred to this genus, descril)cd 

 from very unsatisfactory fragments of lower jaws. Very little is known 

 respecting the characters of the group. 



TILLOMYS SENEX Marsh. 



TiUomya iienex Maksii, Amer. Journ. Sci. and ArU, 3d ser. iv, 1879, 910. 



"About the size of a rat." Length of the lower molar scries ll"""; 

 depth of the lower jaw at the second molar 5°"". Described from a lower- 

 jaw fragment, having the second molar in place. The jaw is described a« 



