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



Some species, like Rhinolophus ferrum-equinum, were formerly believed, 

 even by scientists, to extend uniformly over Europe, Asia and Africa. Of 

 late, however, they have been divided into numerous distinct forms, for in 

 recent years the characters on which* distinctions can be based have re- 

 ceived more careful consideration. These facts should have a stimulating 

 effect upon collecting, since it is certain that, just as in birds, there are many 

 local species. 



Exact information as to the number of species of Chiroptera from the 

 Ethiopian region is not available, but in the whole world there are recog- 

 nized at present, according to G. S. Miller (1907), "about 900 forms of 

 Chiroptera, a number probably representing considerably less than half of 

 what will eventually be known." Andersen's 'Catalogue of Chiroptera' 

 enumerates 228 forms of fruit-bats, among which are 32 Ethiopian species 

 (34 forms). 



A few remarks about the distribution of fruit-bats after our long field 

 experience in eastern and western Africa may clear up some of the intricate 

 details of their range. More than two-thirds of all the fruit-bats known in 

 the Ethiopian region, that is 25 forms, are recorded from the West African 

 province (" Great West African Forest Tract, south to Damaraland, east to 

 Victoria Nyanza," 1 and north to the borders of the Sudan) ; and only ten 

 species from the huge eastern and southern portion. Four of them (Eidolon 

 hehum, Roussettus cegyptiacus , Epomophorus gambianus, Epomophorus 

 anurus) overlap with those of the West African province. Two species 

 occur only in southern Arabia and one only on the Island of Pemba. The 

 latter is a representative of the genus Pteropus, elsewhere unknown in the 

 Ethiopian region. It tends to show, together with Malagasy fruit-bats 

 and other island forms, the isolating influence of the sea, to which the 

 species occurring on the islands off the West Coast do not submit, for all 

 the fruit-bats of Fernando Po, St. Thomas, and Annobon belong to the same 

 forms as those of the neighboring mainland. 



A review of the principal physiographic features involved will probably 

 offer the best explanation of their distribution. The West African rain- 

 forests extend from the shores of the Gulf of Guinea, with a slight interrup- 

 tion near the Gold Coast, eastward to the foot of the Ruwenzori, over a 

 distance of 3000 miles, and form at places a sector more than 400 miles wide 

 (see map, p. 415). The relative absence of important mountains, the gener- 

 ally slight elevation, the typically moist equatorial climate with little or no 

 well-marked seasonal change, are factors that have facilitated the even dis- 



1 Andersen, Knud. Catalogue of the Chiroptera. Vol. I. Megachiroptera. London, 1912. 

 p. Ixvii. 



