1908.] DR. KNUD ANDERSEN ON BATS. 263 



or it must be a mistake ; as a matter of fact, the structure of the 

 teeth in 2X(,rr>ipes is exactly as in jamaicensis, but the size of the 

 teeth on an average slightly smaller ; and the heel of p' is, as 

 might be expected fi'om this, not larger, but on average a tiifle 

 smaller than in jamaicensis. 



Artibeus jamaicensis yucatanicus J. A. Allen. 



1888. Artibeus per.ipiciUatus (pavtim, not L.) Thomas, P. Z. S. p. 129 (21 Feb. 



1888). — Cozumel Island (Yucatan). 

 1897. Artibeus perspicillatus (pavtim, not L.) J. A. Allen & Chapman, Bull. Am. 



Mus. N. H. ix. Art. i. pp. 3-5 (23 Feb. 1897).— Yucatan. 

 1904. Artibeus yucatanicus J. A. Allen, Bull. Am. Mus. N. H. xx. Art. 20, 



pp. 232-33 (29 June, 1904).— Type localitj'; Chiclien Itza (Yucatan). 



Diagnosis. — Similar to A.j. parvipes, but skull and external 

 dimensions averaging a little larger. Zygomatic width of skull 

 16'3-17*2 mm. (average 16"8) ; maxillary tooth-row 9"7-10*2 mm. 

 (average 9"9); forearm 56-61 mm. (average 59'6). 



General characters. — The angular emargination between cusps 

 5 and 7 of ni' is usually as well marked as in any A. planirostris., 

 but individuals occur in which it is distinctly reduced in size. 

 The coloration of the fur of the upper side is generally of the dark 

 type, but light- coloured examples are not rare, especially among 

 individuals with somewhat worn teeth. The facial stripes are 

 usually obsolete or faint. 



A.j. yucatanicus ^n^^L parvipes. — The skull of A. j. yucatanicus 

 is generally a trifle larger (total length 27*4, as against 26'9 mm. 

 in 2)a7-vipes) and, especially, broader (zygomatic width 16"8 mm., 

 against 16"1 mm.) ; the difierence in the size of the teeth is 

 infinitesimal. The forearm and metacarpals of yucatanicus 

 average 2 "5 to 3 mm. longer than in p)arvi'pes ; also the phalanges, 

 tibia, and foot average a little longer. See the detailed measure- 

 ments, p. 264, — The two races come so extremely close to each 

 other, and are practically so difficult to discriminate that, were it 

 not for their difi"erent habitat, they ought not to be kept separate. 



A . j . yucatanicus a.nd jamaicensis. — A.j. yucatanicus forms a 

 transition between the Cuban A.j. par vipes and the Central 

 American (and Mexican, and West Indian) A. j. jamaicensis. 

 Externally yucatanicus is indistinguishable from jamaicensis, 

 there being not even an average difference in size ; but in the 

 size of the skull and teeth it is decidedly nearer to parvipes than 

 to jamaicensis. 



Sp)ecimens examined. — 14 specimens (7 skins) and 11 skulls, 

 from the following localities : — 



British Museum : — N. Yucatan (1) ; Cozumel I. (1). — Skulls of 

 both specimens. 



U.S. National Museum * : — Yucatan (4) ; Merida, Yucatan (1) ; 

 Progreso, Yucatan (3) ; Chichen Itza, Yucatan (3) ; Belize (1). — 

 9 skulls, from all the localities enumerated. 



* U.S. N. M. nos. 11445 (37547), 108153-55, 108489-91, 143119-22. 



