1908.] DR. KNUD ANDERSEN ON BATS. 243 



2)lanirostris described in this paper. The largest skull available 

 IS 3 mm. longer, 2-3 mm. broader (zygomatic width) than the 

 largest skull of A. p. planirostris ; the upper tooth-row, in the 

 largest specimen, is 1-2 mm. longer than in the largest A. p. plani- 

 rostris ; there is approximately the same difference between the 

 smallest skull of A. p.fallax and the smallest of A. p. planirostris, 

 nnd the average difierence in the size of the skull and teeth is, 

 consequently, very well marked. The difference in^ the external 

 dimensions is equally pronounced, A. p. fallax being, as a rule, 

 noticeably larger than A . p. planirostris. See the table of measure- 

 ments, p. 246. 



I have had no real difficulty in discriminating any individual 

 of A. p. fallax, in the whole large series examined, from A. p. 

 planirostris ; only one unusually small specimen of the former 

 race from Demerara (B.M. no. 75.11.3.17) caused me some hesi- 

 tation. Nevertheless, A. p. fallax cannot, in my opinion, be 

 separated as a distinct species, but only as a local raceof Artibeus 

 jjlanirostris, for the following reasons -.—First, there is no struc- 

 tural difference, in any respect, hei^een A. p. fallax and the other 

 races ; second, small individuals of A. p.fallax come so exceedingly 

 near to large individuals of A. p. jdanirostris that there can be 

 no doubt that, occasionally, the two forms will prove to be practi- 

 cally quite indistinguishable ; third, some examples of A. p.fallax 

 from the Lower Orinoco Valley (Ciudad Bolivar) and Para show 

 decidedly leanings towards A. p. 'planirostris, and there at least, in 

 the border districts between the areas occupied by the two races, 

 they will, no doubt, be found to intergrade. 



Hpecimens examined. — 55 specimens (42 skins) and 36 skulls, 

 from the following localities : — 



British Museum :— Para (2).— French Guiana: Cayenne (8). 

 —British Guiana: Demerara (6); Oomachka, Demerara River 

 (5) ; Essequibo River (20) ; Kanuku Mts., about 59° W., 3° N. 

 (11) ; B. Guiana (1).— Lower Orinoco : La Vuelta, Ciudad Bolivar 

 (2). — 36 skulls, from all the localities enumerated. 



Eange.—Gfmi\.ns., extending southward to Para, where it meets 

 .1. p. p)lanirostris, northward to the Lower Orinoco Yalley, where 

 it also meets A. p. planirostris. 



If Rehn's Artibeus hercides, from E. Peru, and a specimen of 

 A. jjlanirostris recorded by Oldfield Thomas {I. s. c.) from Caiza, 

 S. Bolivia, neither of which has been examined by me, are referable 

 to A. p. fallax, the range of this form is considerably more 

 extensive. 



Peters's A. fallax, 1865.— The species was based on " einem 

 weiblichen Exemplar in Weingeist " from Guiana in the Berlin 

 Museum, and " anderen trockenen Exemplaren " in the Leyden 

 Museum (probably specimens b and c in Jentink's ' Cat. Syst. 

 Mamm,' p. 208, 1888). According to Peters {I. s. c.) A. fallax is 

 in size, in the form of the ears and nose-leaves, and in colour 

 " dem A. p)erspiGillatus [^A. jamaicensis of the present paper] 



