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Bulletin American Museum of Natural History. [Vol. XXXVII, 



Expedition prove that the range of many of these fruit-bats extends, as 

 might be expected, across the entire West African province. Of the larger 

 and more gregarious forms, that for many reasons can be more easily ob- 

 served, we know with certainty that they are found not only across the 

 rain-forest but far beyond into the drier regions in many of the larger 

 forested galleries. The range of several of the small and rarer forms known 

 only from a few localities was considerably enlarged by our observations 

 and will undoubtedly be still more extended as the knowledge of African 

 bats increases through the more detailed results of further explorations. 



Fruit-bats of course reach much larger dimensions, and their body is 

 relatively heavier, than is the case with insectivorous bats. But size alone 

 offers no real point of distinction, as is shown by a comparison of the meas- 

 urements of the largest and smallest African bats of each group. 



Fruit-bats Total length Wing-spread 



Hammer-headed bat (Hypsignathus monstrosus), 



male . 10 . 25 inches 3 feet 2 inches 



Pygmy fruit-bat (Megaloglossus woermanni) 2 . 75 inches 10 . 25 inches 

 Insectivorous bats 



Black hawk-bat (Saccolaimus peli), female 6.1 inches 2 feet 3 inches 



Mouse pipistrelle (Pipistrellus musciculus), female 2 . 5 inches 6 . 5 inches 



The Malay flying-fox (Pteropus edulis), measuring one foot in length and 

 5 feet across its fully expanded wings, holds the record for size among the 

 Chiroptera. 



Dull shades of brown generally predominate in the fur of African fruit- 

 bats and help to render them inconspicuous when at rest. To distinguish 

 them at once from their insectivorous compatriots, two external charac- 

 teristics give ready clues. 



1. The form of the ear (Fig. 1, B, p. 407), with its borders coming together 

 below, differs from that of insectivorous bats, where a space intervenes between the 

 lower edges of the anterior and posterior margins (Fig. 1, A, p. 407). 



2. The second digit, forming the edge of the wing, bears a terminal claw (Plate 

 XLIV, Fig. 1), not present in any insectivorous bat. 



The thumb is long and well developed, bearing a claw as in all other 

 bats, but here sufficiently strong to sustain their weight when climbing about 

 on the branches. It is also used, together with the foot, to help hold the 

 fruit when feeding, thus really functioning as a finger. The claw on the 

 second digit considerably increases the use of the wing as a hand. The 

 third finger is always the longest, the fourth and fifth the shortest. In 

 Eidolon hehum, which has the widest distribution and is also the greatest 

 traveler among African fruit-bats, the third digit is especially long and the 



