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



these bats can set their sail, as one might say. This arrangement would 

 help to explain the extraordinary skill of these fast fliers in steering about. 



Out of ten females, three taken in June and December, each had a single 

 foetus. Therefore we may state that they have one young and breed at 

 different seasons. 



Throughout the year, shortly after nightfall, but especially on moonlight 

 nights, a dozen or more of these skillful flyers may be observed sailing 

 swiftly over the open village places. Usually they travel at a height of 

 some 30 feet or more but very often when diving after their prey they come 

 down in such elegant and rapid swoops as to resemble more a hawk than a 

 bat. One can then distinctly hear the reiterated short chirping or squeaking 

 notes uttered during flight. In foggy weather they fly very low, since 

 the insects upon which they feed are evidently forced by the dampness to 

 keep close to the ground. During the daytime they retreat into hollow trees 

 where they cling to the walls singly, not forming clusters as the bulldog or 

 molossine bats habitually do. Though their feeding grounds are chiefly 

 the open places about human settlements we never found them in houses 

 like Taphozous mauritianus . We often wondered why they disappear again 

 so soon, but a specimen shot only half an hour after their arrival in the village 

 clearing had its stomach already gorged with the well-chewed remains of 

 tiny insects. 



They may be considered typical of the region of equatorial rain-forests, 

 as they seem to be absent from the bushveldt to the north of Niangara, 

 although in the latter place they are still common. The large forest galleries 

 along the Uele and its affluents evidently still furnish a suitable environment. 



The range of this bat extends all across Tropical Africa from the Gold 

 Coast and Kamerun to East Africa, though for the latter record the exact 

 locality is not known. 



12. Coleura gallarum nilosa Thomas. 



Externally this bat is a small copy of Taphozous Sudani, with the hair 

 sooty-brown, becoming whitish at the bases. The thumb however is rela- 

 tively longer, and the tail slightly shorter, though it protrudes above the 

 interfemoral membrane. The gular sac is but slightly developed. The tip 

 of the wing folds back exactly as it does in Taphozous and Saccolaimus; 

 moreover the joint that thus becomes virtually the tip of the folded wing is 

 protected by a pad-like thickening of the skin, no doubt preventing injury 

 from the rough rocky walls of its home. Expanse of wings 11.5 inches 

 (290 mm.), total length 3 inches (77 mm.), tail .62 of an inch (16 mm.). 



The region of Aba, whence all our specimens come, is on the divide 

 between the Congo and Nile basins; but this is not to be pictured as an 



