554 THE APLODONTIA. 
been a stumbling-block and a matter of doubt, in 
creat measure attributable to the fact that but a 
single species of the genus is known, and very 
few specimens have hitherto been obtamed. A 
fine male specimen has recently been set up in 
the British Museum collection, that I caught near 
my camp on the prairie. 
In many particulars the Aplodontia very nearly 
resembles the Spermophiles, particularly the 
prairie-dog (Cynomys Ludovicciana), but differs, 
as in the true squirrels, in the rootless molars and 
absence of post-orbital processes. In this respect 
it is allied to the beaver. It is quite impossible 
to assign it a well-defined and settled position, 
until a greater number of specimens are pro- 
cured, from which more minute and careful exa- 
mination of the bony and internal anatomy can 
be made. At present, however, it would appear 
to connect the beavers with the squirrels, through 
the Spermophiles. 
The name Lewis and Clark gave this animal, 
Sewellel, is evidently a corruption of an Indian 
word. The Chinook Indians, once a powerful 
tribe, live near the mouth of the Columbia ; and 
from them, in all probability, Lewis and Clark 
obtained the name, and first heard of the animal. 
But the Chinook name for the Aplodontia is Og- 
