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Show COUES ON GEOMYS AND THOMOMYS-T. CLUSIUS. 265 of talpoides and its conspecies I know of. The color is equally diagnostic. We miss the peculiar blackish area in which the ears of all other Thomomys are set, and we find instead a blackish snout. The pallid yellowish-gray of the upper parts is as different from any of the interminable variations of color of other Thomomys as that of Geomys castanops in comparison with G. bursa-?'ius. The whiteness of the fur to the very roots, on the under parts, is a striking character. The specimen was procured in a region where the true talpoides is also found in abundance. It seems to be the fortune of monographers who have found it necessary to reduce various species previously established to geographical races or mere synonyms, that they should have at the same time new ones of their own to propose. But I see no help for this. New species are not, to me, the altogether desirable things they seem to some; and my growing dislike to find them out keeps pace with my increasing knowledge of our ignorance respecting old species; nevertheless, there is no escape from them at present, at frequent intervals, and of course the sooner they are-all indexed binomially the better. Having no material for the further elucidation of the characters of Thomomys clusius, I may close with the remark that, if the unique specimen is not a pure " sport," it is a perfectly good species. The name chosen for this species commemorates a peculiar trait of the whole family Geomyidce-their remarkable and not generally known habit of plugging up the numerous openings of their extensive subterranean tunnels. This name, in connection with several others, completes a sort of epitome of the history of the family. They are underground animals (Geomys) that throw up heaps of earth ($G)JUO$, a pile-Thomomys) and close the entrances of their excavations (clusius]; they are mole-like in many respects (talpoides) ; they are peculiarly provided with pouches (bursarius) ; and they feed on roots (bulbworus) 34 COL |
