[100] Other plants found here, were the great sunflower Helianthus giganteus, Asclepias obtusifolia, Ph., A. viridiflora, Ph., A. syriaca, and A. incarnata, Amorpha canescens, N., Erigeron pumilum, N., A. Veronica approaching V. deccabunga Scuttellaria galericulata, Rumex venosus, N., and several which are believed to be undescribed.—James.
[101] In rain water puddles, we remarked a new species of Branchiopode belonging to the genus Apus; small crustaceous animals, which exhibit a miniature resemblance to the King or Horse-shoe Crab, (Himulus polyphemus,) of our sea coast, but which are furnished with about sixty pairs of feet, and swim upon their back. The basins of water, which contained them, had been very much diminished by evaporation and infiltration, and were now crowded to excess, principally with the apus, great numbers of which were dying upon the surrounding mud, whence the water had receded. This species is distinguished from the productus of Bosc, and montagui of Leach, by not having the dorsal carina prolonged in a point behind; and from cancriformis, by the greater proportional width of the thorax, and more obtuse emargination behind. The length of the thorax along the middle, is three-tenths of an inch, and its greatest breadth somewhat more. It may be named Apus obtusus.
A very large species of Cypris, also inhabits these small rainwater pools in great numbers, of which the valves are more than one-fifth of an inch in length.—James.
[102] North Platte River rises in Laramie County, Colorado, in the high valley called North Park, enclosed by the Park Range and the Medicine Bow Mountains. It flows north to Natrona County, in central Wyoming, and thence turns to the southeast.—Ed.
[103] Castor fiber.—Some of the European naturalists appear to be in doubt, whether or not the beavers of Europe are of the same species with ours, from the circumstance of the former not erecting habitations for themselves, thus appearing to differ at least in habit, from the North American, (which are usually but improperly called, Canada beaver, as they are not confined to Canada, but are found far south in the United States, and east to the confluence of the Ohio and Mississippi,) but it is possible, that the aboriginal manners of the European beavers, corresponded with those of ours, and that necessity, resulting from the population of the country by civilized man, compelled them to resort to a different mode of life, to escape the certain destruction, with which the great demand for their fur threatened them. But as the European beaver is smaller than ours, other naturalists have regarded it as a distinct species. In those districts of country of North America, from which they have not yet been exterminated, and which are populated by the whites, as particularly on the Mississippi, above the Ohio, and below St. Louis, we have not heard that they build, but it is more than probable, that, as in Europe, they change their mode of life, in order to be the more effectually concealed from view. From subsequent observation, we have learned, that the beaver does not attempt to dam large streams, perceiving at once the impracticability of the undertaking: his object in damming a stream appears to be, to preserve a constancy in the height of the water, in order that the entrance to his habitation in the bank may be concealed, and that the curious conical edifice may not be destroyed by a sudden flood, or too much exposed by a deficiency of water.
An Indian informed us, that in his time, he has caught three specimens of this animal, that had each a large white spot on the breast. Singular accounts of this animal are given us by the hunters, but which we had no opportunity of verifying.
Three beavers were seen cutting down a large cotton-wood tree; when they had made considerable progress, one of them retired to a short distance, and took his station in the water, looking steadfastly at the top of the tree. As soon as he perceived the top begin to move towards its fall, he gave notice of the danger to his companions, who were still at work, gnawing at its base, by slapping his tail upon the surface of the water, and they immediately ran from the tree out of harm's way.
The spring beaver are much better for commerce than those of the autumn and early winter, as the fur is longer and more dense. But the beaver taken in the vicinity of the Rocky Mountains is almost equally good during the year.
Mr. Frazer, a gentleman who has been several years engaged in the fur trade, in the interior of North America, on the Columbia, and in North California, in speaking of the beaver, mentioned a circumstance, which we do not remember to have seen recorded. The lodges are usually so placed, that the animals ascend the stream some distance to arrive at the spot whence they procure their food. They make their excursions under water, and they have, at equal distances, excavations under the bank, called washes, into which they go and raise their heads above the surface, in order to breathe, without exposing themselves to be seen. In winter the position of these washes is ascertained, by the hollow sound the ground returns when beaten; and the beavers are sometimes taken, by being pursued into these holes, the entrances to which are afterwards closed.
Otters are frequent on the Missouri. We had an opportunity of seeing on the ice of Boyer Creek a considerable number of the tracks or paths of otters; they were the more readily distinguishable, from there being snow of but little depth on the ice, and they appeared as if the animal was accustomed to slide in his movements on the ice, as there were, in the first place, the impressions of two feet, then a long mark clear of snow a distance of three or four feet, then the impressions of the feet of the animal, after which the sliding mark, and so on alternately. These paths were numerous, and passed between the bank and a situation, where a hole had been in the ice, now frozen over.—James.