770 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
to S. langsdorffi of three of the specimens there mentioned. He says fur- 
thermore that he believed the large Squirrels of Brazil were referable to 
several species,* which he in this paper attempts to characterize. The dif- 
ferences he mentions, however, either in size or color, are by no means im- 
portant, in view of the usual range of variation presented by the American 
Sciuri. He restricts, however, the S. dangsdorffi to specimens strictly reier- 
able to Brandt’s original description, or those having the dorsal surface varied 
with ochre-yellow and, black, and the lower parts ochry-rust-yellow, with a 
small spot of white on the throat; the fore limbs pale yellow, sprinkled with 
black ; the hind limbs similarly colored, but more reddish ; the tail black at 
the base, mixed with pale yellow, passing toward the end into orange-red. 
The nine examples he refers to this species he says are all of the same color, 
and all come, according to Natterer, from Cuyaba, in the province of Matto 
Grosso, Brazil. According to his measurements, this species is the smallest 
of the four he here recognizes. ; 
The seven specimens he refers to S. igniventris are all from Marabita- 
nas, on the Upper Rio Negro. Four of them are red, the remaining three 
black. Two of the red specimens have the hairs of the back black, with 
light points, which in one are reddish-yellow, in the other grayish-yellow; 
so that in one the dorsal surface is rust-red sprinkled with black, in the other 
rust-yellow sprinkled with black. The under side of the body is beautiful 
rust-red. The tail is black at the base, but mostly red at the surface, with 
the hairs black basally, somewhat mixed with yellow. The size is given as 
a little larger than that of S. dangsdorfi. This species he says differs from 
both S. dangsdorffi and S. pyrrhonotus through its color and its habitat, and 
from the former also in size. 
The nine specimens of S. pyrrhonotus were (except one) all collected 
by Natterer near the mouth of the Rio Madeira. The color above is lively 
rust-red, inclining anteriorly more to orange-red and _ posteriorly becoming 
fiery-red ; below, whitish-yellow or ochre-yellow, lightest anteriorly. The 
tail is, as in the other species, black at the base, passing into rust-red or rust- 
yellow, with the hairs broadly black at the base. The eight specimens col- 
lected by Natterer are said to be all of the same color; the ninth, from Spix’s 
**Seitdem habe ich nun die ganze Sammlung von Natterer vergleichen kéanen und bin dadureh 
mit ihm zur Ueberzeugung gelangt, dass nicht nur meine 3 vorhin genannten Exemplare gar nicht dem 
Sciurus langscorfit angehoren, sondern dass unter den grossen brasilischen Eichhérnehen mehrere Arten 
zu unterscheiden seyen, wie ich dies nun auseinander setzen will”’—({ Abhandl. der math.-physik. Classe 
Bayer. Akad. der Wissensch. v, 274.) 
