1! 



DR. KNUD ANDERSEN ON BATS. 



207 



{Lonchoglossa f. i.) p^ is the smallest. From this it is concluded 

 that the upper premolar lost in Stenodermatous bats is p^ (not, 

 as in Rhinolophidae, p'^). 



Pg, if present in Phyllostomatidfe, is generally smaller than p^ 

 and p^ (compare £. i. Micr^onycteris). From this it is concluded 

 that the lower j)remolar lost in Stenodermatous bats is p^, not p^. 



Upper incisors (text-figs. 41 A, d). — Inner pair bifid, the two cusps 

 subequal in length (the inner one generally a trifle longer) ; front 

 face plane or faintly convex, with slightly wrinkled enamel; hinder 

 face strongly concave in direction from above downwards, the lower 

 half of the crown of the tooth therefore somewhat chisel-shaped. 

 Outer pair as broad as inner pair, but much shorter ; cutting- 

 edge simple (not bifid), oblique ; front face as well as hinder face 

 concave from side to side. The reason why the outer is con- 

 siderably shorter than the inner incisor, and its cutting- edge 



Text-fig. 40. 



A B 



Hhinoloplms trifoliatus, ? ad. Singapore. B.M. 48.23.1. 



A. Riglit upper, B. Left lower tooth-row, exclusive of incisors ; as a paradigma of 

 structure of molars in insectivorous bats, for comparison with dentition of 

 Artibeus, text-fig. 41. X f. 



For explanation of lettering of cusps (1, 2, .3, 4, o, 6, 7) see text, p. 205. 



difierently shaped, will be readily understood when studying the 

 way in which the lower work against the upper teeth : — the long 

 and very strong lower canines pass in front of the outer upper 

 incisors, completely covei-ing their front face, with exception of 

 their narrow inner margin (text-fig. 41 d) ; this circumstance it is 

 which has effected a decrease in the size of the outer incisors, 

 made their front face concave (by constant wear against the tips 

 of the lower canines), and the inner tip of the cutting-edge (next 

 to inner incisors), which is less exposed to the pressure of the 

 lower canine, longer than the outer tip of the cutting-edge (next 

 to the upper canines), which is most exposed to the pressure of 

 the lower canine. 



Lovjer incisors (text-figs. 41 B, d). — All four teeth subequal in 

 Proc. Zool. Soc— 1908, No. XIY. 14 



