TAY MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
The measurements of these species, as given by authors (mainly by 
Wagner), are as follows :— 
S z 
ae g 
ea \ aa 
Name. Locality. eS a = Quoted from— 
s° 33 ° 
ne esi |e 
A Re a ea | 
toa a Ss] g 
Sciuraus variabilis ........-..-- Kester Pera) sccc.=)scn=aeie ae eee 10.00 | 10.00} 11.25 | 1.50 | Tschudi. 
Sciurus langsdorfii. - Cuyuba, Matto Grosso, Brazil ---| 10.84 9.08 | 11.50 | 1.00 | Wagner. 
DOre sara eee eae eee IPPV A Rgds saskeoaeecesscosSsoscs CRS Fes sese 12.00 | 1.00 | Brandt. 
Sciurus igniventris ..........-- Rio wNegro; Branil sec sces=s.cr eerie WG eee 13,00 | 1.00 | Wagner, 
Sciurus pyrrhonotus..---..- .--.| Mouth of Rio Maceira, Brazil. ....-----.| 11.25 | 10.16 | 13.16 | 1.00 |....do. 
Sciurus tricolor. ........-...---. Northern yh ert sens ecto ese seee eae 12.34 | 11.00] 13.50 | 1.08 |.-.-do. 
Do. ss scinctaccseoecaceas BERR ett ipa sea seSonni acts hcaneoaee eSaocic pea iri ses ese bese 31 (Sere Tschudi. 
Sciurus stramineus ............- Ompatope; Pern -2. noe see eee HOLOO) | sesecaee 100} sees Eydoux. 
My single specimen (a mounted example) from Manaos, Brazil, exceeds 
the largest of these measurements by nearly an inch (Knglish seale), but 
agrees in coloration with Wagner’s S. pyrrhonotus. As, however, the meas- 
urements given in the table are in the larger German inches, the difference 
is more apparent than real. The whole range of variation in size and color 
is not greater than usually occurs among the Sciuri, and is even far less 
than is often met with. There is the same style of coloration in all; the 
same short, thin, stiff pelage and long, pointed ears. The coloration of the 
lower parts in all is sharply separated from that of the upper surface of the 
hody, reference to. which is made by almost every author in describing these 
several supposed species. The lower surface varies only in the amount of 
rufous, being, in some specimens, only pale soiled or yellowish-white, in 
others bright rust, with numerous intermediate stages in others. The dorsa 
surface varies in respect to the greater or less prevalence of black or red, and 
in the tint of the red, which is sometimes yellowish-red, sometimes dark rust- 
red. The anterior half of the body is generally lighter than the posterior 
half, the color generally increasing in intensity posteriorly. All have the tail 
more or less red at the base, passing into yellowish-red or deeper red 
posteriorly. 
According to Tschudi, only S. “stramineus” occurs west of the Andes, 
this species having been obtained by the naturalists of the ‘ Bonite” at 
Omatope, in Northwestern Peru, near Payta. S. variabilis he gives as ranging 
chiefly in the upper forest region, east of the main Andean chain, and as not 
often occurring below 2,000 feet. Between 9° and 12° south latitude, it is 
