RODENTIA—SCIURINAE. 279 
CONCLUDING REMARKS. 
In the preceding pages I have presented at considerable length all the species of squirrels which 
I have been able to identify as inhabitants of North America, north of Mexico. There are still 
a good many species credited to the same region, which it may be as well to notice briefly for the 
sake of completing the history of the genus. Comparatively few of these, however, if any, 
will ever be detected within our limits, as the unexampled scientific activity of the government 
expeditions and private parties that have recently traversed this continent in every direction, 
have left few localities unexplored. 
A considerable number of these residuary species were described at an early date by Dr. Bach- 
man, as coming from ‘‘ California.’ Most of them are, however, probably natives of Mexico, 
which, in its southern regions especially, abounds in large squirrels with bushy tails, and so 
variable in color as to render it exceedingly difficult to say how many species really exist. 
These Mexican squirrels are actually more varied in tint than those of the United States, the 
upper parts often showing the same white, yellow, or red, as the belly, in large isolated patches— 
a character rarely, if ever, seen in the more northern species. In the many species described 
by different authors, and the entire lack of Mexican specimens, I shall not pretend to determine 
the actual number of species really existing, or to settle the question of priority of description. 
I shall merely enumerate all that have been credited to Mexico and Central America. 
The species of Dr. Bachman may have been brought from the southern part of Sonora, 
Mexico—the distinction between the lower and upper parts of this State not being as carefully 
drawn twenty years ago as now. It is to be regretted that no mention is made of the collector 
of his specimens, or of the circumstances under which they were gathered ; we are equally 
ignorant of the place where they were deposited at the time of description, or where they are 
now. It is possible that Sciwrus leporinus and lanigerus have a real existence as North American 
squirrels, and that the former may really be an immature S. fossor. 
I shall first proceed to enumerate the residuary species described as North American by 
Audubon and Bachman; then the Californian, Mexican, and Central American species, of other 
authors; then the South American bushy tailed species ; and conclude with a list of all the species 
referred to, alphabetically arranged, with an indication of the page of this report where they 
are mentioned. 
A Sciurus clarkii; figured by Major C. Hamilton Smith, from a specimen in the old Peale’s 
Museum of Philadelphia, said to have been brought by Lewis and Clark from the Missouri 
country, furnishes no characters by which it can be identified with any distinct North American 
species. It is reasonable to presume that there is some error in the locality as given, since 
Lewis and Clark make no mention of such an animal in their very full notices of the zoology 
of the regions explored by them.! 
Sciurvus crank, Smith, Hab., Missouri river ?—Sciurus clarkii, Smira, Griff., Cuvier, III, 1827; 189, plate. 
“Back, upper part of the head, and neck, cheeks, and tail, of a delicate silver gray color; the shoulders, flank, belly, 
and posterior extremities, both within and without, white, with a slight ochrey tint ; on the sides of the nose and the fore arms 
this tint deepens in intensity. he head is rather flatted and thick ; the ears small’and round ; the eyes far apart, leaving 
a wide expanse of forehead ; nostrils semi-lunar—the upper lip cleft; a black spot on the chin. Tail flat and spreading, 
