MOLOSSI. 403 



femoral membrane is retractile, being movable backwards and for- 

 wards along the tail, or (in Mystacina only, see p. 443) can be very 

 completely folded up upon itself and hidden away like the wings. 



The strength of the anterior and posterior limbs, the development 

 of the callosities at the base of the thumbs, the large flat feet with 

 thickened outer and inner toes, the freedom of the forearms, thumbs, 

 and feet from the volar membranes, which are very perfectly folded 

 away (in repose), indicate collectively that the species of this Sub- 

 family are, of all Bats, most fitted for terrestrial progression ; and 

 this induction is confirmed by those who have observed their habits. 

 (See notes on the habits of ' Molossus ohscurus, M. glaudaus, and 

 Nyctinomus hrasiliensis.) 



Group MOLOSSI. 



Ears large and broad, generally united ; tragus small ; muzzle 

 broad, obtuse, obliquely truncated ; nostrils opening by circular 

 apertures, their projecting margins terminating the muzzle in front; 

 first phalanx of the middle finger folded (in repose) on the back of 

 the metacarpal bone ; legs very short and strong ; feet broad, the 

 outer and inner toes much thickened and larger than the others, and 

 furnished with long curved prehensile hairs ; tail thick, produced 

 far beyond the posterior margin of the interfemoral membrane ; 

 brain-case thick, flat, and broad. 



In aU the species the upper lip is very thick, and often deeply 

 furrowed by vertical wrinkles, evidence of its great expansibility. 

 The wings are very narrow, and the middle finger very long, its 

 metacarpal bone in most species slightly exceeding the total length 

 of the last finger. The first phalanx of the middle finger is short, 

 less than half the length of the metacarpal bone, on the dorsal surface 

 of which it is folded forwards in repose. The interfemoral membrane 

 sheaths the base of the tail, and is movable at the wiU of the animal 

 backwards or forwards upon it, thus increasing or diminishing its 

 surface. 



The great length and narrowness of the wings indicate rapid flight ; 

 and the power possessed by these Bats of varying the extent of surface 

 of the interfemoral membrane must confer upon them great dexterity 

 in quickly changing the direction of their flight, as when obliged to 

 double in pursuing their swiftly flying insect prey ; while the ex- 

 tremely expansible lips evidently aid them especially in capturing 

 during rapid flight, and in maintaining their hold on, the large 

 round-bodied Coleoptera. Of aU Bats the Molossi appear especially 

 suited by their peculiar conformation for capturing the most rapidly 

 flying insects, which, no doubt, form the greater portion of their 

 food. Their large and very strong acutely tubercular teeth would 

 enable them to crush with ease the hard armour of the larger Coleo- 

 ptera. 



(For remarks on habits &c., see notes under descriptions of 

 species.) 



2d2 



