1915.] — Allen, Review of the South American Sciuride. 149 
A word respecting the origin of the present paper seems pertinent. 
Owing to the scarcity of authentically determined South American mammal 
material in American museums, including especially type material, I took 
with me early in 1913 some 600 specimens of small mammals recently re- 
ceived from our collectors in Colombia and Ecuador for direct comparison 
with the historic material in the British Museum. No monographic work 
was then contemplated, only the identification of my own material. Al- 
though my time was limited, I was able to devote about three weeks to the 
study of the South American Sciuride, which enabled me to become fairly 
familiar with the extensive British Museum series of these animals, as I 
listed nearly all the specimens, with their localities and other data, including 
collectors’ measurements when present. I also studied carefully such types 
as had direct bearing upon my own material, and intended to take in hand 
all of the sciurid types from South America, although I had not then de- 
cided to take up the group comprehensively, but lack of time prevented, 
greatly to my subsequent regret, for on returning to the American Museum 
I soon decided to take up the squirrel group collectively, on the basis of my 
British Museum notes and the material in American museums. This plan 
has worked out quite satisfactorily except in the case of a few of Gray’s 
types, which I had failed to examine. To remedy this omission, and to 
reinvestigate a few doubtful points, I had fully arranged for another visit 
to London when the breaking out of the present European war rendered this 
plan impracticable, greatly to my disappointment and embarrassment. 
The present paper is therefore presented with some misgivings, but I trust 
the labor expended upon it will not prove wholly futile. 
It is needless to say that the material I have examined is wholly inade- 
quate for anything like a final revision of the subject. It has been enough 
to show how great are the deficiencies, which only time and future field 
work can supply. Even the Guianas and southeastern Venezuela are among 
the regions poorly represented in the present material; while from the vast 
area of Brazil there is only enough to afford an outline of the sciurid fauna. 
And the same is nearly true of Peru and Bolivia. 
The present paper includes South America and Panama as far north 
as the Canal Zone, the forms of Microsciurus which occur north of this 
boundary, and the Sciwrus hoffmanni group as represented in Chiriqul and 
Costa Rica, these being South American types. The extralimital forms 
comprise the following species and subspecies: Microsciurus alfari alfare 
Allen, Microsciurus alfart browni Bangs, Microscvurus boquetensis Nelson, 
Mesosciurus hoffmanni hoffmanni (Peters), Mesosciurus hoffmanna chiriquen- 
sis Bangs. 
