NATURAL SCIENCES OF PHILADELPHIA. 135 



the foot. Rich fulvous, or even fawn-color, similar below but 

 paler, variously obscured on the back with dusky ; tail and feet 

 usually dark ; face and mouth-parts sooty-blackish, strongly con- 

 trasting with white pouch lining. Southern Interior and lower 

 California. c umbrinus. 



B. Small ; decidedly less than six inches long. Hind foot less than 

 an inch, fore foot still less. Tail scarcely one-fourth as long as head 

 and body. Above, pale yellowish-gray, with a shade of light 

 brown ; below, entirely white ; feet and tail white. Ears minute, 

 not set in a blackish area; end of snout blackish. Bridger's Pass, 

 R. Mts. 2. clusius, n. s. 



1. Thomomys talpoides (Rich.), Baird. 



Gricetus talpoides, 1 Rich., Zool. Journ. iii. App. 1828, 518. 



Geomys talpoides, Rich., F. B. A. i. 1829, 204. 



Saccophorus talpoides, Fisch., Syn. 1829, 588 (marked "388"). 



(Compiled.) 

 Ascomys talpoides, Wagn., Suppl. Schreb. iii. 1843, 390. (Compiled.) 

 Pseudostoma talpoides, A. and B., Q. N. A. iii. 1853, 43, pi. 110. 



(Compiled.) 

 Geomys (Thomomys) talpoides, Gieb., Saug. 1855, 530. (Compiled.) 

 Thomomys talpoides, Baird, M. N. A. 1857, 403. (Compi ed.) 

 Geomys borealis, " Rich.," Bach., Journ. Phila. Acad. 1839, 103. 

 Ascomys borealis, Wagn., Suppl. Schreb. iii. 1843, 391. (Compiled.) 

 Saccophorus borealis, Gray, List Mamm. Br. Mus. 1843, 149. (Mere 



mention.) 

 Pseudostoma borealis, A. and B., Q. N. A. iii. 1853, 198, pi. 142. 

 Thomomys borealis, Baird, M. N. A. 1857, 396, pi. 22, figs. 2 a-e. 

 Geomyx townsendii, Bach., Journ. Phila. Acad. 1839, 105. 

 Ascomys townsendii, Wagn., Suppl. Schreb. iii. 1843, 391. (Compiled.) 

 Thomomys rufescens, Maxim., N. Act. Ac. C. L. xix. 1839, 383. Bd. 



M. N. A. 1857, 397. 

 Ascomys rufescens, Wagn., Suppl. Schreb. iii. 1843, 387. (Compiled.) 

 Geomys rufescens, Le C, these Proceedings, 1852, 1G1. 

 Geomys (Thomomys) rufescens, Gieb., Saug. 1855, 530. 

 Thomomys "fulvus," Merr., U. S. Geol. Surv. Terr, for 1872, 1873, 



665, lapsu. 

 " Geomys unisulcatus, Gray, Mus. Brit." 



Char, mediocr. Coloration almost exactlj' like that of the 

 house rat, Mus decumanus ; sometimes assuming a more reddish 

 phase, occasionally blackish-plumbeous ; tail and feet white, and 



1 Although this name is of frequent occurrence in the books, no author 

 has hitherto identified it ; all the accounts are compiled. The only advance 

 upon Richardson's original description is Audubon's figure of the type spe- 

 cimen. 



