PARACHUTING 283 



the air. These squirrels are also credited with a certain amount 

 of steering power as they descend in graceful curves from branch 

 to branch or tree to tree. 



The smaller Fly ing- Squirrels (species of Sciuropterus], repre- 

 sented in Asia, North-east Europe, and North America, are 

 extremely graceful and pretty animals, which in most respects 

 resemble their larger relatives. But the eyes are much larger, 

 and even the base of the large tail is perfectly free. Being 

 flattened from above downwards, this organ adds considerably 

 to the area of the surface presented to the air. Audubon and 

 Bachman thus describe the movements of the American Flying- 

 Squirrel (Sciiiropterus volucella], a community of which came under 

 their observation: " At times one would be seen darting from 

 the topmost branches of a tall oak, and with wide extended mem- 

 branes and outspread tail gliding diagonally through the air, till it 

 reached the foot of a tree about fifty yards off, when, at the moment 

 we expected to see it strike the earth, it suddenly turned upwards 

 and alighted in the body of the tree. It would then run to the 

 top, and once more precipitate itself from the upper branches and 

 sail back again to the tree it had just left. Crowds of these little 

 creatures joined in these sportive gambols; there could not have 

 been less than two hundred. Scores of them would leave each 

 tree at the same moment, seeming to have no other object in view 

 than to indulge a playful propensity." This account certainly 

 seems to furnish some evidence of steering power. 



The African Flying -Squirrels (species of Anomalurus and 

 Idiurus) are of somewhat smaller size than the Brown Flying- 

 Squirrel and the species related to it. Notwithstanding an agree- 

 ment with these both in general build, and especially as regards 

 the nature and arrangement of the parachute folds, there are 

 differences of sufficient importance to justify the inclusion of the 

 African forms in a special family (Anomaluridcz). One of these 

 is the absence of a piece of gristle stretching from the wrist along 

 the front edge of the lateral fold. But the place of this is taken 

 by a rod of similar character that runs from the elbow to the 

 side of the fold. The other characteristic feature is the presence 

 of a series of overlapping scales on the under side of the tail at 

 its base. These would appear to be used as a help to climbing. 

 In fig. 823 a drawing is given of a Gold Coast species (Anoma- 

 peli] to illustrate these features. 



