ROCKY MOUNTAIN FLYING-SQUIRREL. 
208 
sabrinus from Quebec, the following appeared to be the points of difference : 
alpinus is considerably the larger animal, and although the legs appear 
somewhat shorter, they are stouter ; the fur is more dense and longer, 
having quite a woolly appearance ; the ears are shorter than in P. sabrinvs, 
and are broader and more rounded. They may also be distinguished by 
the colour of their fur from each other, that of alpinus on the under surface 
being pure white from the roots, while the fur of P. sabrinus is tinged with 
yellowish. The most striking difference, however, is the extreme shortness 
of the bony process which supports the flying membrane at the fore-leg. 
By some mistake of the engraver the numerals referring to the figures 
were misplaced— the upper and larger figure, marked figure 1, should have 
been figure 2, as it represents the present species (P. alpinus ), and of course 
the lower figure, which is marked figure 2, should have been figure 1 ; it 
represents P. sabrinus. Our subscribers will please alter the figures on 
the plate accordingly. 
