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Show 232 EXPLOitATION OF THE OARONS OF THE COLORADO. ance; if the vertebrre be left in, it shrinks tightly around them in drying, displaying not only the joints, but also the shape of the individual· bones. The hind feet share this nakedness, but not to the same extent; the instep is nearly bare, but the toes are sparsely pilous with short colorless bristles. 'fhe back of the fore feet is in much the same condition. The depilation of the members is not always as complete as here described; but such is the nnmistakable tendency in all cases, and such the uccompli:shed result in the majority of examples in adult life. Younger specimens, in the plumbago state of pelage, show as hairy tail and feet as an average sample of G. bursariu~, and before the incisors have attained maturity, so as to afford fhir characters, might readily be supposed to be G. bursa·riu~, were locality not taken into ac.count. Of such character is No. 1500, Museum of the Smithsonian Institution, particularly mentioned by Baird, op. c·it., p. 382. My material is abundant for a taule of measurements of this species; hut it seems unnecessary to prepare one, ince it would be imply an amplification of the statement that the animal does not differ at all from G. bursa·rius in size or shape. For the same reason, it is unnecessary to enter into further description after presenting the two characters (particular style of sulcation of incisors ancl nakedness of tail and feet) iu which solely does the species stunrl apart from G. bursm·ius. Under these circumstances, it might be held by some that the present is merely n localize-d race of G. bursarius; and I should be the last one to dispute uch statement of an abstract fact. This Geomys is, of course, an offshoot of the bursarius stock; and, for that matter, so are all the rest of the "specie "modified descendants of orne one stock. It would be only shifting the qucst.ion a peg to require that the fact shoulrl affect the nomenclature. A "permanent variety" is a contradiction in tcrrns. This is the ca c: Here is a set of individuals differing thus-and-thus (as above described) from another set. rrhc difference is slight, but constant; there is no intergradation, fill' the simple reason that the two cts of animals uow occupy different geographical areas, are completely isolated from each other, and thus cut ofl' f'ro 1n interbreeding; or, in other word , from rcproducin1Y off81>rin 1r in which the • b . b characters of both parents arc blended. It is quite po siblc that, in their bliud movements under the grounu, the two may come together ancl interbreed ; COUES ON GEOMYS AND TllOMOMYS-G. OASTANOPS. 233 but we must wait for this to occur, and be attested by intergracling specimens, before we need hesitate to describe G. tuza as a "distinct species." The earliest notice specially referable here appears to be the unmistakable description by S. L. Mitch ill of the "Hamster of Georgia," and various allusions are made by other writers to the same animal. The Mus tuza * of Ord unquestionably belongs here, being based upon Mitchill's animal. A short though expressive diugno is is given by Rafinesque, with unwonted accuracy, of Geomy.~ pinetis. This name, or its emended form G. pineti, has been generally applied, excepting by Audubon and Bachman, who, ignoring Rafinesque, rename the animal jloridana, and refer it to Say's genus Pseudostoma. The species puts in the customary second-hand appearance under the su pcrvision of several systematic com pilcrs, few, if any, of whom appear to have had much knowledge of their own upon the subject. The geographical distribution of the species is remarl<ably limited. I have no knowledge of its occurrence anywhere excepting in Georgia, Florida, and Alabama. The Savannah River is said to form a complete barrier to its northward extension. Its westward limit is not so precisely defined; but it does not appear to reach to the Mississippi, where tbe other species is found. Audubon and Bachman have nothing particular to say of the habits of this species in com pari son with G. bur sari us, beyond the statement that it does not become dormant in winter. The best account of its habits, and particularly of its moclc of constructing its underground galleries, is Dr. Gesner's article above quoted. GEOMYS CASTANOPS, (Brl.) Lee. P11eudostoma oastanop11, llAIHD1 Stansbury's Rop. Groat Salt Lake, 1852, 313.!....AuD. & B.&.cu., Q. N. A. iii, 18[>4, 304. Geon&yB casta~topB, LEe., Proo. Aca<l. Nat Sci. Phila. 1832, 163.-D.uno, llf. N. A. 1857, 381.-D.&.rnD, P.R. R. Rep. x, 1er,9, Gunnison LLnd lloclnvith's Routo, Mumm. 8, pl. 10, f. 2. Ge01:,ys olal'kii, llAmo, Proc. Acad. Nut. Sci. Philo..18G5, 33~.-llAmD, M. N. A. 1857, 38.'3, pl. 50, figs. 1a-g.K~ tNNJt~tJ.Y1 P.R. R. Rop. x, 18&9, Whipple's Route, Mo.mm. 13.-BAmD, U. S. Mox. Bouncl. Snrvcy, ii, pt.. ii, 1859, Mumm. p. -, -.-Oimn., Co.t. Bonos Br. Mus. 1862, 222. ChcHtlmt-faced, and Pecos Gopher, llAIRD1 ll. co. DIAONOSIS.-Supcrior incisors with a single median groove bisecting the iitec cxnctly. Fore feet shorter, or not longer than hind feet; these aud the "Evidently tho samo worcln!! tu()t,, lu:n, lucan, &c. 30 oor. |