INTRODUCTION. XXI 



in the frugivorous to the posterior molars (see p. 16 and footnote, 

 also p. 512). 



Among the Microchiroptera, in the family Phyllostomidae alone 

 is there any marked departure from the insectivorous type of den- 

 tition, and there only in the limited groups Stenodermata (see 

 Plates XXVIII. and XXIX.) and Desmodontes (see pp. 445, 511, 

 545). 



In the Megachtroptera, which are whoUy frugivorous, the form 

 of the teeth is remarkably similar throughout the different species, 

 though their number is very variable. In all the species (except 

 Cynopterus latidens, Plate V. fig. 3) the molar teeth are longer than 

 broad, and their crowns are traversed by a longitudinal groove ; 

 while among the species of Microchiroptera, in Sturnira lilium 

 alone are the molar teeth somewhat similarly grooved (Plate 

 XXVIII. fig. 5). 



The milk-dentition is much the same in all Bats. The teeth are 

 very slender and with acutely pointed recurved cusps, evidently 

 very effective in retaining a secure hold on the nipple of the mother 

 during flight. They are soon shed, but often coexist for a short 

 time with the permanent teeth, when the latter are considerably 

 elevated above the gum. 



Alimentarx Canal. 



The opening of the mouth is anterior in most species, but in 

 many of the species of Emballonuridce it resembles that of the 

 Insectivora in being inferior, the extremity of the nose being more 

 or less produced beyond the lower lip, so much so in Rhynchonyc- 

 teris naso (Plate XX. fig. 4) as to resemble that of the Shrew-mice. 

 In the Nycteridoe, and in the groups Mormopes and Desmodontes, 

 the lower lip projects slightly beyond the upper. In all the insec- 

 tivorous species the gape is wide, and the lips are fringed with 

 straight hairs and very expansible, especially in the Molossi, in 

 many species of which they are marked by deep vertical wrinkles 

 (Plate XXII.). In Chalinolohus a small lobe projects horizontally 

 outwards from the lower lip near the angle of the mouth, and adds 

 considerably to its width. In the Mormopes the lower lip is much 

 expanded in front and fringed with foliaceous cutaneous appendages, 

 which probably fulfil the same functions as the nasal processes in 

 the leaf-nosed Bats ; whUe in the remaining species of Phyllostomidoe 

 and in the Nycteridce the same part is furnished with variously 



c 



