SClUlllJ-)yE— EXTINCT Hl'EClES. 



S)!'.;") 



posterior diameter of lower incisor 0.17; transverse 0.125. Dcscribctl anJ 

 figured l)y Dr. Leidy (/. c.) from tlic greater jjortion of a lefl- mandil)ular 

 ramus and several detached molar teeth. From Fort Bridger, Utali, and also 

 reported by Professor Cope (/. c.) from Cottonwood ('recii and Black's Fork, 

 Southwestern Wyoming. 



PARAMYS DELICATISSIMUS Leidy. 



I'aramtjs dclivatitimua Leidy, Proc. Acad. Nnt. Sci. Pbilft. 1871,231 ; Ann. Rop. U. 8. Ocol. Siirv. Tun: lor 

 1871 (1872), 357; Extinct Vert. Fauna, 1873, 112, 33.'-., pi. vi, figs. 28, 29.— Ciu-i!, Pal. Bull, 

 no. 12, 1873, 4. 



Smaller than either of the preceding, and from tiie same localities. 

 liCngth of tiie lower molar series C'jO of an inch ; antero-posterior diameter 

 of the lower incisor 0.125 ; transverse 0.083. Described and figured by Dr. 

 Leidy (/. c.) from "the greater portion of the right ramus of a lower jaw, 

 containing all the molars, and a second specimen consisting of a small frag- 

 ment of another lower jaw containing the second molar". Fort Bridger 

 {Ltikly) and Black's Fork {Cope). 



Genus SCIURAVUS Marsh. \ 



Sdwattti Mahsh, Aiuer. Jonrn. Sci. and Arts, 3d ser. ii, 1871, 122. 



U|)per molars with two pairs of tubercles, and a minute intermediate 

 cone on the outer edge. The lower incisors extend below the entire molar 

 series. 



SCIURAVUS NniDUS Marsh. 



&ii(rotiii» in7irfH« Marsh, Araer. Jouru. Sci. 3d sur. ii, 1871, 128.— Leidv, Ann. Rep. U. S. Geol. Surv. Terr, 

 for 1871 (1872), 308. 



"About the size of the Brown Rat {Mus decumanus)^ Described from 

 a portion of an upper jaw containing the last three molars. Found at Grizzly 

 Buttes, near Fort Bridger, Wyoming. 



SCIURAVUS UNDANS Marsh. 



Sriiirauiw nii(ffl«« MAnsH, Amer. Joum. Sci. and Arts, 3d ser. ii, 1871, 122.— Lbidy, Ann. Rop. II. S. Gcol. 



Surv. Terr, for 1871 (1872), 358. 

 Panmgt undana Cope, Pal. Bull. no. 12, 1873, 4. 



Rather larger than the Brown Rat {Mas dccumanus) ; smaller than 

 Paramys dclicatissimus Leidy. Described by Professor Marsh (/. c.) from a 

 portion of a lower jaw containing the incisors and the first three molars, from 



m 



