NATURAL SCIENCES OF PHILADELPHIA. 131 



Analysis of Sjoecies. 



A. Superior incisors bisulcate ; fore claws enormous ; pouches very large. 



a. Upper incisors almost exactly bisected by the large groove, with the 

 fine marginal groove distinct ; tail and feet hairy. . . bursarius. 



b. Upper incisors divided by the main groove into two unequal portions, 

 of which the inner is the larger, and the fine groove faint or obsolete ; 

 tail and feet nearly naked tuza. 



B. Superior incisors unisulcate ; fore claws and pouches smaller. 



c. Superior incisors exactly bisected ; fur soft ; tail and feet hairy. 



e. Smaller ; yellowish-brown ; below whitish. . . castanops. 



f. Larger ; dark reddish-brown ; below plumbeous. . mexicanus. 



d. Superior incisors unequally divided by the groove into a smaller 

 inner, and larger outer moiety ; pelage hirsute ; tail and feet nearly 

 naked. .......... hirsutus. 



1. Geomys bursarius (Shaw), Rich. 



Mus bursarius^ Shaw, Linn. Tr. v. 1800, 227, f. 8 ; G. Z. ii. 1801, 100, 



pi. 138. 

 Cricetus bursareus, Desm., Mamm. ii. 1822, 312. 

 Saccophorus bursarius, Kuhl, Beit. 1820, 65. 

 Pseudostoma bursaria, Say, Long's Exp. R, Mts. i. 1823, 40G. Aud. 



and Bach., Q. K A. i. 1849, 332, pi. 44. 

 Geomys? bursarius, Rich., F. B. A. i. 1829, 203. 

 Ascomys bursarius, Eyd. and Gerv., V T oy. Favorite, v. 1839, 23. 

 Geomys (Saccophorus) bursarius, Gieb., Saug. 1855, 529. 

 Geomys bursarius, Bd., M. N. A. 1857, 372, pi. 22, fig. 1 a-h, pi. 50, fig. 



2 a-g, and of most late writers. Leidy, these Proceedings, 18G7, 97 



(Loess of Missouri). 

 ? Mus ludovi'cianus, Ord., Guthrie's Geog. 2d Am. ed. ii. 1815, 292. 

 ? Diplostoma fusca, Raf., Am. Month. Mag. ii. 1817, 44. 

 ? Diplostoma alba, Raf., 1. c. 

 Saccophorus? albus, Fisch., Syn. 1827, 305. 

 ? Geomys cinereus, Raf., op. cit. 45. 



Mus saccatus, Mitch., N. Y. Med. Repos. xxi. 1821, 249. 

 Ascomys canadensis, Licht., Abh. Acad. Wiss. Berl. 1823, 13, fig. 

 Geomys canadensis, Le C, these Proceedings, 1852, 158. 

 ? Geomys drummondii, Rich., Rep. Brit. Assoc, for 1836, v. 1837, 157 



(sp. indet. dentibus prim, bisulcatis). 

 ? Ascomys drmnmondii, Wagn. Suppl. Schreber. 

 Geomys oregonensis, Le C, op. cit. 160 (assigned locality erroneous). 

 Geomys breviceps, Baird, these Proceedings, 1855, 334 ; M. N. A. 1857, 



378, pi. 52, fig. 2 a-g. 



1 Only the original references, with a few of the principal additional ones, 

 are given here ; the complete bibliography will appear elsewhere. 



