1917.] Lang and Chapin, Distribution and Ecology of African Chiroptera. 491 



As we might expect from such highly specialized forms, insectivorous 

 bats at times display abilities which place them among the most successful 

 predatory types. Their brain-case is comparatively large, and their skull 

 shows a greater diversity in form than that of any other suborder of the 

 Mammalia. It clearly demonstrates how feeding-habits and the food to be 

 masticated or digested completely change the shape of the skull, the denti- 

 tion and, in some cases, even the digestive organs (Phyllostomida?, Desmo- 

 dontidse). Among the bats of the Ethiopian region we cannot point out 

 equally striking differences, but two skulls illustrated in this paper show the 

 point in question. The heavy skull of Mops (Allomops) osborni (Fig. 12, 

 p. 470), with an enormous sagittal and lambdoid crest, is capable of giv- 

 ing strong support to large muscles of mastication. They are needed to 

 operate the broad grinding, cutting surfaces of the short dental rows. 

 The food of all such Molossidse consists chiefly of hard-shelled insects. On 

 the other hand the globose, smooth skull of Kerivoula cuprosa (Fig. 8, p. 452) 

 offers support for only small muscles. The rostrum is strongly pinched 

 together. The teeth are narrower, and the tooth-rows and palate longer. 

 Their food consists of tiny mosquitos and similar insects. 



The great width of their gape (p. 531) assists them in feeding rapidly, 

 for many of these insects disappear as quickly as they come. This wide- 

 open mouth acts as a net and every insect entering is instantly put to death 

 by the sharp dagger-like canines. The short tooth-row serves as an ex- 

 ceptionally efficient milling apparatus. They literally cut and grind their 

 prey to dust with a few bites, an exceptional advantage when we consider 

 that speedy digestion is thereby made possible. For only by pulverizing 

 or separating their food in this manner are the muscles of these minute and 

 often hard-shelled insects instantly exposed to the digestive fluids. Bats, 

 having no crop like a bird in which to store away their food, thus succeed 

 in extracting all there is in the food in the quickest possible manner. We 

 observed Hipposideros gig as niagarce feeding on termites so ravenously that, 

 after filling its stomach, it tucked into its cheeks all they could hold. It 

 also had its mouth full when shot. 



The wings show considerable variety and are either narrow and pointed, 

 as in those that fly as swiftly as swallows, or are broad and rounded, as in 

 those that flutter about apparently in the aimless fashion of butterflies. 

 They all have a short, clawed thumb (p. 549) and four greatly elongated 

 fingers which "serve like masts that keep the canvas of a sail spread and 

 regulate its motions," as Goldsmith picturesquely writes. 



Besides serving as mere supports during flight, the wing and inter- 

 femoral membrane have another very important function. Together with 

 the large nose-leaves and curiously modified ears of certain species, they 



