244 DR. KNUD ANDERSEN ON BATS. [Apr. 7, 



tiiuschencl alinlich und gewiss audi sclion oft mit ihm verwechselt 

 woi'den," but differs in the following respects : " Der untere Rand 

 des Hufeisens ist langer, deutlicher abgesetzt und fein gekerbt. 

 Das Gebiss ist namentlich dadurch verschieden, dass der zweite 

 obere walire Backzahn am hinteren Rande hinter dem Zacken 

 des Cingulums [cusp 5 of this paper] viel tiefer eingebuchtet ist, 

 und dass hier ein sehr kleiner flinfter Backzahn sich hineinlegt." 

 — This statement, taken together with the locality, leaves no 

 doubt as to the identification of A . fallax. 



Rehn's ^. AercM^es, 1902. — Type locality: Eastern Peru; two 

 specimens (one skull). Its " general characters " were summed 

 up by Rehn {I. s. c.) as follows : — " Allied to A. planirostris (Spix), 

 but differing in the larger size, the much larger foot, and in 

 numerous dental character's." These latter are thus described : — 

 " Second upper premolar subquadrate in basal outline, quite 

 different from the subpyriform tooth of A. 2^^(^ii'irostris, the in- 

 ternal node well developed and forming a conspicuous cusp. First 

 upper molar broad, deep, the anterior inner angle more developed 

 than in A. planirosft'is, which species has this portion rounded. 

 Second lower premolar very heavy and broad, the posterior in- 

 ternal ' border with the dentate ridge low. First lower molar 

 subquadrate in outline." Upper tooth- row 12, lower tooth-row 

 12'5, maxillary width across m^ 14"5 mm, ; foi'earm 65*2, 3rd 

 metacarpal 61*5, tibia 24 mm. 



Rehn had for comparison two A. p)l<^nirostris from " Chapada 

 [Matto Grosso], Brazil " ; so it was quite natui-al that he found the 

 large, large-skulled and large-toothed Peruvian bat considerably 

 different in size. But if he had been able to compare it with 

 A. p. fallax, he would have seen that the size of the two Peruvian 

 examples is in everj^ respect precisely as in the Guianan form 

 described long ago by Peters. If, further, he had had a tolerably 

 good series of skulls of A. p. fallax and ^. p. planirostris, he woiild 

 have realised that the dental characters as derived from the 

 single skull of A. hercides examined by him have neither specific 

 nor subspecific importance, but are individual peculiarities, found 

 in any form of A. planirostris (as, indeed, t\\ej are found also 

 in the vaiious forms of A. jamaicensis). As to this latter point 

 I subjoin the following details : — p*, in a series of six skulls of 

 A. p. fallax (B.M. nos. 3.4.5.22-27), all of adult individuals, 

 none with the teeth much worn, all from Cayenne and taken 

 almost on the same date : basal outline subpyriform in two skulls ; 

 subquadrate with strongly rounded inner margin, in one ; sub- 

 quadrate with slightly rounded inner margin, in one ; subquadrate 

 with straight inner margin, in one ; strongly subquadrate (nearly 

 quadrate) with straight inner margin, in one. The antero-internal 

 cusp on the heel ("internal node," Rehn) of p* varies, in this 

 series, from small, through strong, to very strong ; the cusp is not 

 always most conspicuous in quite unworn teeth. m\ in the same 

 series from Cayenne : — one extreme (two skulls) : short antero- 

 posteriorly, broad from side to side, antero-internal angle quite 



