Rodents from West Africa^ &c. 199 



notch 9*5 ; breadth of brain-case 6* I ; front of canine to back 

 of m^ 3-9. 



Hah. Efulen, Cameroons. 



Type. Male. B.M. no. 4. 2. 8. 8. Collected by Mr. G. L. 

 Bates. 



This bat shares with the larger P. crassulus of the same 

 region, also discovered by Mr. Bates, a disproportionately 

 short forearm, the length of this member being less than has 

 been hitherto recorded in any Pipistrelle, and nearly the least 

 of any known bat. From P. minusculus^ Miller, apparently 

 its nearest ally, P. nanulus may be readily distinguished by 

 its rounded ears and other differences in detail. 



Kerivoula bicolor, sp. n. 



A small species with white-tipped wings. 



Size very small, but little larger than K. pusilla and 

 K. minuta. Build liglit and delicate throughout. Ears of 

 medium length, reaching, when laid forward, just to the tip 

 of the nose ; inner margin strongly convex ; tip blunt, the 

 concavity below it not deep. Tragus as in K. pusilla, a 

 slight concavity above the process at its outer base. Wings 

 to the base of the toes. Calcars extending three-fifths of the 

 distance towards the tip of the tail. 



Fur of medium length ; hairs of back about 7 mm. long 

 (10 mm. in K. minuta). Wings practically naked, the base 

 of the interfemoral membrane thinly clothed, and with a few 

 fine hairs on its posterior margin not forming a continuous 

 fringe. Hind legs and feet well covered with longish hairs. 



Colour of head and body above (in spirit) apparently fawn- 

 colour or drab, below pure sharply contrasted white. Wings 

 drab-brown, changing abruptly to pure white at their outer 

 ends. On one wing of the type the white extends inwards 

 to about the line of the fifth finger, running also halfway 

 along the edge of the membrane towards the foot ; on the other 

 wing it is confined to the part outwards of a line drawn from 

 the tip of the index to the tip of the fourth digit ; probably 

 its exact extent is always variable. 



Upper incisors slender, bicuspid; the main cusp of the 

 outer reaching to the tip of the secondary cusp of the inner 

 incisor. Upper premolars with their antero-posterior con- 

 siderably exceeding their transverse diameter, the first slightly 

 larger than the second and smaller than the third. 



Dimensions of the type (measured in spirit) : — 



Forearm 29 mm. 



Head and body 35; tail 36; ear 12*5; tragus on inner 



14* 



