RODENTIA—CASTORINAE—CASTOR CANADENSIS. 361 
The American beaver being satisfactorily shown to be distinct from the old world animal, of 
course, cannot continue to be called Castor jiber. For the proper specific appellation we have two 
names, canadensis of Kuhl, and americanus of F. Cuvier. The date of the former is 1820; the 
precise place where the latter name is introduced I have not been able to ascertain. The Hist. 
des Mammiféres du Mus. is usually given as the reference, but here the animal is merely called 
Le Castor du Canada in the 6th fasciculus (1819,) According to Brandt, F. Cuvier first broached 
his views of the difference of the species, in the 51st fasciculus of this work, 1825, and there 
probably gave the name; but this I am not able to verify at present, not having part 51 at 
hand. At any rate the point of priority seems to be settled clearly in favor of Kuhl’s name. 
The American beaver has a very wide distribution throughout North America, being found 
from the Polar seas to the Rio Grande, and the Gila on the south, or to, at least, latitude 26° on the 
east side of the continent, (the mouth of the Rio Grande.) Formerly it extended from the At- 
lantic to the Pacific, but it is at present very rare east of the Missouri. A few are still found in 
the Adirondac region of New York, as also in the Alleghanies of Pennsylvania, Virginia, North 
Carolina, and even Alabama, according to some accounts. Their remains in the bone caves of 
Pennsylvania are very numerous, showing that they were once very abundant there. 
At one time the fur of the beaver was very valuable, and an extensive trade was carried on, 
so that the animal rapidly diminished in numbers. The substitution of silk, and the introdue- 
tion of the nutria fur, (Myopotamus coypus of South America,) has greatly reduced the demand 
and the price, so that now beaver fur is not worth more than a few dollars a pound. In conse- 
sequence, it scarcely pays the expenses of a systematic and laborious pursuit on the part of the 
trapper, and the beaver is again multiplying very rapidly, sothat the western streams are 
becoming rapidly stocked again. 
Fossil American Beaver.—The bone caves at Carlisle yielded a large number of remains of 
beaver, both young and old. There are no satisfactory points of difference from the existing 
‘species, although in size some of the teeth are larger than any recent specimens I have seen, 
indicating a length of quite six inches for the skull. There are a good many jaws, with the 
anterior deciduous first molar still implanted. These are provided with distinct roots. The 
upper one has three roots, one broad posterior one, and two anterior ; the exterior one longer 
and a little forward of the other. The lower molar has two roots, one posterior very broad, the 
anterior smaller. The patterns of the teeth do not differ essentially from their successors, 
although the crowns are narrower. 
