252 Mr. O. Thomas on new 



Head and body 50 ; tail 14 ; lower leg and foot (s. u.) 30'5 ; 

 calcar 18'5. 



Skull : greatest length 15'6 ; basal length in middle line 

 12 ; greatest breadth 10-4 ; interorbital breadth 4*2 ; breadth 

 of brain-case 8 ; palate length 5*4 ; front of upper canine to 

 back of m' 6*5 ; front of lower canine to back of m^ 6*8. 



Flab, (of type). Teapa, Tabasco, S.E. Mexico. Other 

 specimens from Guatemala and Costa Rica. 



Ti/pe. Female. B.M. no. 88. 8. 8. 20. Collected by 

 II. H. Smith, and presented by Messrs. O. Salvin and F. D, 

 Godman. About a dozen specimens examined. 



The large members (forearms 45-50 mm.) of the restricted 

 genus Saccopteryx are remarkably uniform in character over 

 a wide geographical area, series from Ecuador and Peru on 

 the west to Pernambuco on the east and Trinidad and Guiana 

 in the north presenting no differences not covered by indi- 

 vidual variation at single localities. I am therefore quite 

 unable to distinguish Mr. Miller's S. persjncillifer (forearm 

 45-50) of Trinidad from the original S. bilineata (forearm 

 45 mm.) of Surinam. The large skull with heavy postorbital 

 processes, as described by Miller, is equally to be found in 

 specimens from Guiana, Para, and Pernambuco, which must 

 among tliem include the true bilineata of Surinam. Examples 

 with the typical length of forearm (45 mm.) occur both 

 among our Trinidad and Guianan series, without any cranial 

 indication that they belong to a different form from those 

 whose forearms attain to 48 or 50 mm. 



In Central America, liovvever, the representative of S. bi- 

 lineata seems sufficiently modified to bear a subspecific 

 name, being distinguished by its lighter skull, more cube- 

 shaped brain-case, smaller teeth, and rather duller coloration. 

 But even then the difference is but slight. 



The still smaller species of this group are two in number — 

 S. leptura, Schr., browner in colour, with a skull of about 

 13*5-14 mm,, and a forearm averaging about 38-40 mm. ; and 

 S. canescens, Thos., grey, skull only 12*5-13 mm., and length 

 of forearm about 36-38 mm. Of the last-named, besides the 

 type from the Lower Amazon, the Museum contains examples 

 from the Orinoco {Cherrie), Surinam {Bartlett), and Cayenne 

 {Che7'rie)j in each of which places S. leptura also occurs. 



Balaniiopteryx io, sp. n. 

 A slenderly built species allied to B. infasca *. 

 Size very small, the trunk and forearm lengths markedly 



* Saccopleryx infusca, Thos. Auu. & Mag. Nat. Hist. (6; xx. p. 546 

 (1897). 



