1908.] DR. KNUD ANDERSEN ON BATS. 235 



and its alveolus are wanting on the other side ; in two skulls 

 {A. p. fallax, $ ad., British Guiana, teeth ahiiost unworn, B.M. 

 no. 6.4.8.11 ; and A. p. jjlanirostris, § ad., Bahia, teeth unworn, 

 U.S. N. M. no. 102457) is m' entirely wanting on both sides, and 

 in one of these latter skulls (102457) also m^ is entirely lost on one 

 side. Thus, only 3 per. cent, of the large series of skulls of adults 

 examined have entirely lost m^ on both sides. 



It is of some importance to emphasise that the disappearance of 

 m^ in A . planirostris is a very rare individual abei'ration, inasmuch 

 as the presence of this small tooth is in many cases the only 

 character by which A. planirostris can be safely discriminated 

 from A . jamaicensis. 



Tragus. — In most individuals there are 4 or 5 small serrations 

 on the outer margin of the tragus, above the median projection ; 

 the serrations may be sharp, but as a rule they are more or less 

 rounded off, often reduced to inconspicuous nodules, sometimes 

 almost obliterated. The variation is quite individual. 



NoseAeaves. — According to Dobson, the anterior margin of the 

 horseshoe in A. planirostris is " free, separated from the nnizzle 

 straight, unnotched," and the author of the British Museum 

 Catalogue of Chiroptera lays much stress on this character as a 

 difference between A . planirostris and A. jamaicensis ("^. «er- 

 spicillatus'"). In a majority of individuals of A. 2ylanirostris the 

 front margin of the horseshoe is distinctly " free," but there is 

 every intermediate stage from this condition, thi'ough a margin 

 clearly '' bound down," though still more or less projecting, to a 

 margin so completely fastened down as to be almost continuous 

 with the integument of the muzzle. As a similar (or, if anything, 

 still greatei-) variation in this respect occurs in A . jamaicensis the 

 character is quite useless for a discrimination of these two species. 

 — The margin of the horseshoe is sometimes simple, sometimes 

 crenulate in front, sometimes crenulate all round ; the ci^enulation 

 occasionally extends to the margins of the lancet. — The lateral 

 margins of the horseshoe are not rarely bent up so as to form a 

 fold, suggesting the condition characteristic of Uroderma. 



Hairing on limbs and inter/em oral. — The proximal half or two- 

 thirds of the forearm, the metacarpal of the pollex, the upper side 

 of the femur (the tip, as a rule, excepted), and the base of the 

 interfemoral next to the body and the femur, are densely haired. 

 The tip of the femur and the whole of the tibia covered with so 

 short and sparse hairs as to appear almost naked. The toes from 

 the tarsus to the base of the claws, clothed with rather long 

 coarse hairs. 



Colour. — Young individuals: — Upper side from shoulders back- 

 ward dark and dull smoky brown, this colour confined to the 

 distal third or fourth of the hairs ; base of hairs slate. On the 

 anterior part of the upper side, from the shoulders forwai-d the 

 hair-bases are distinctly lighter, almost smoke-grey. Under side 

 dark smoke-grey, with a peculiar mottled appearance, due to the 

 very short, almost greyish-white tips to the hairs. Tips of wings 



