. Monographs of North American rodentia [microform]. Rodentia; Paleontology; Rongeurs; Paléontologie. 248 MONOGRAPIiS OF NORTH AMERICAN RODENTIA. ilW ii. uniform ".izzle of gray, black, and luteous or fulvous, and below muddy-gray, rustier on the breast. It may be, indeed, tiiat tliese differences are somewhat regular and seasonal, as well as the change to white; but as few of our speci- mens are marked for season, we cannot make this out. As, however, several of our richest-colored skins arc spring and early summer ones, we judge that, with the disappearance in spring of the white winter
. Monographs of North American rodentia [microform]. Rodentia; Paleontology; Rongeurs; Paléontologie. 248 MONOGRAPIiS OF NORTH AMERICAN RODENTIA. ilW ii. uniform ".izzle of gray, black, and luteous or fulvous, and below muddy-gray, rustier on the breast. It may be, indeed, tiiat tliese differences are somewhat regular and seasonal, as well as the change to white; but as few of our speci- mens are marked for season, we cannot make this out. As, however, several of our richest-colored skins arc spring and early summer ones, we judge that, with the disappearance in spring of the white winter-coat, the brightest, sharpest pelage is put on, the vividness of the rufous or mahogany attaining a maximum in the breeding-season, or rather a little at\erward, in midsummer; and that subsequently tlie hues grow cooler and more intimately mixed, until at length in the fall the whitening becomes manifest. Winter.—In perfect dress, the animal is pure white all over. In the fall, the whitening seems to begin underneath and on the sides, to progress then over the lower back; the heavy color of the upper back and breast being the last to yield. Several specimens are white, with a narrow dorsrl rea of color, that spreads forward over the upper back and shoulder, and underneath still tinges the breast; others are curiously white, with lateral rufous stripes that nearly meet on the rump and then curve round the sides to the chest; others are pure white, except a sharp spinal stripe of grayish-black ; some are white, uniformly tinged willi pale rufous all )ver. But it would be idle to attempt an enumeration of all the intermediate stages; although, in the midst of appa- rently interminable changes, doubtless rules of very general applicability may be deduced from observation of a few hundred specimens accurately marked for season. The two middle fore claws attain their maximum of development in winter. In spring and early summer, these claws do not appear very differ- ent from thos
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Keywords: ., bookcentury1800, bookdecade1870, bookpub, booksubjectpaleontology
