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Show 248 EXPLORATION OF 'l.'BE OARONS OF TBE COLORADO. Of these eight. species which Professor Baird gave, one, "talpoides," is not really iuclentified hy him, as he only copies Richardson's account; unrl auothcr, b01·ealis, he says himself he fhilcd to recognize satisfactorily. This leaves only six which he actually indorsed "Borealis" had already been identified by LeConte with rufesans; and the nnimal I describe as "tn1poides" is the same us his under another name, resulting from the identification with it of Richanlson's species. Another name is thus diposed of. 'rhat Wootlhousc's "fulvus" is an nbsolute synouym of what Baird called umbrinus, I have satis{ierl my elf by inspcctiou of his type-specimen. Rc~pccting the Pacific-coast form, it is perfectly easy to t rucc the complete intcrgradution between the northern (douglasi) nnd ~outhcrn (bulbivorus) extreme. Of "luticcps," no second specimen is known ; ~ome of the external characters are altered, nppnrcntly, by skinning and drying after immersion in alcohol. In accounts of the ~pecics of this genu~, much stress has been luid u pun size and shape as di~tingui bing marks, even by tho::;e who arc fully aware, not only of the high normal variability in these respects, but ahw of t.hc peculiar susceptibility to overstuffing, aud to various distortions of parts. Nowhere else, perhaps, has bad taxidermy made such a .. break; it is responsible for diflcrcnt genera, to ay nothing of various species. The skin of the whole body, li.ke that of the pouch, is extremely distcnsi blc, and several inches may be added to the stature of any individual by overst.uinng, wit.hout leaving nny very obvious trace. The peculiar configuration .of the. body at the ba ·c of the tail renders uicc measurement of that member very difficult. The feet., particularly the fore feet, shrink and crump in drying, so that neither their size nor their hn.pe can be appreciated. Upon removal of the skull, the mouthparts iniullihly lose all semblance of nat.urc in drying. In Geomys, it is tho same; but there the species arc so well marked that the worst taxitlermy can hardly obscure them. After careful examination of many specimens, fi·c 11, alcoholic, nnd dried, the following is the full extent of the discriminations 1 have been able to make: Sizc.-'l'he Northern Interior form and the Pacific-coa"t form nrc 0 {' the same size; the Southern Interior form averages an inch or two ]c in total length than the other; but large spccimcus of the latter, aud small exam pies of the two former, overlap each other in statu rc. Form.- 1,hc N ort hem I nt.crior rae and theN ort horn sty leH of .t.hc Paci fie· OOUES ON GEOMYS AND TBOMOMYS. 24» coast race have larger fore claws than tho Southern style of the Pacific-coast race or than the Southern Interior race. The difference i sufficient to make the whole hand of the fimncr about equal to the foot., while, in the latter, the hand is ut<ually shorter than the foot. But this is only true as a rule; there arc many exceptions. In all three of the forms, the tail, measured from its true base, ranges from one-third to one-half the total length of head and body, though only rarely reaching either of these extremes. Nothing can be predicated on this score. Color.-The Northern Interior race is a rat-colored animal, hoary-gray underneath, with white tail und feet, much white about the mouth, and no sooty-bluckish there. The Pacific-coast race i a rich dark-brown animal, muddy-bellied, with du ky tail an<l feet, wholly or in part., and sooty about the mouth. 'rhc Southern Interior race is usually n rich tawny or fulvou animal, with partly <lurk tail or feet, or bot h, sooty mouth-parts, and white pouches. This mcc is particularly variable in color; and, in every respect of color, all the races how much variation, and, moreover, intergrade completely. The various form under which the genus Thomomys is exhibited may be discriminated, as fur a::~ it is possible to do so, by the following characters: A. Large. llind foot an inch or more long. Tail nt ltast onc-thinl a.s long as head and body. Above brown, reddish, &c. Below gray, brown, reddish, &c. (not white). Ears in a blackish area well dcvclopc<L---- 1. TALPOIDES. a. Six to eight inchc:s long; f()re claws highly developed (0.45 to O.f>5long), maki11g the hand about as long a!:! the foot. Color of the house-rut, with white tnil and feet, and usually white about the mouth and throat; no contra~ts of dark color about the mouth. Northern Int.erior--- a. talpoides. b. Seven to nine inches long; fore claws less developed, usually under 0.50, leaving tho hand shorter than the foot. Reddish-brown, the bel1y mucldy-brownish, feet and tail usually not entirely white; mouth-parts dark, contrasting with white of the pouch-lining. Pacific coast.-... b. bulbivorus. 32 om, |
