NYCTALUS 253 



basal length of skull, 15 to 16 mm. ; forearm, 39 to 43 mm. ; 

 basal portion of fur conspicuously darkened. 



Colour. — The colour is usually a brown, darker than in N. 

 noctula, nearly the prout-brown of Ridgway, with or without a 

 lighter, wood-brown tinge, and usually showing drab or isabella 

 reflections in certain lights, the underparts not so dark as back ; 

 hairs everywhere blackish (seal-brown) through basal half. Ears 

 and membranes (dry) blackish. Two skins are a pale buffy wood- 

 brown throughout except for the usual dark bases of the hairs. 



Slcull and teeth. — Except for its smaller size and more delicate 

 structure the skull does not differ appreciably from that of 

 Nyctalus noctula. Teeth essentially as in the larger species, but 

 crown area of upper incisors nearly equal, and lower incisor row 

 forming a deeper, almost V-shaped convexity. 



Measurements. — External measurements of adult male from 

 Co. Wicklow, Ireland : head and body, 60 ; tail, 39 ; tibia, 16-2 ; 

 foot, 8 • 2 ; forearm, 42 ; third finger, 78 ; fourth finger, 48 ; ear 

 from meatus, 13. Adult female from Co. Armagh, Ireland : 

 head and body, 63 ; tail, 42 ; tibia, 16 • 6 ; foot, 8 ; forearm, 42 ; 

 third finger, 76 ; fifth finger, 49 ; ear from meatus, 14 ; width 

 of ear, 14. Two adults from Welford, Warwickshire, England : 

 forearm, 40 • 4 and 41-4. Adult from Meiringen, Bern, Switzer- 

 land : forearm, 40. For cranial measurements see Table, 

 p. 255. 



Specimens examined. — Eleven, from the following localities : — 

 Ibeland : Belfast, 1 ; Bray, Co. Wicklow, 2 ; Co. Armagh, 2. 

 England : Mexbro', Yorkshire, 1 ; Welford, Warwickshire, 2 ; Cleeve 

 Priory, 1 ; no exact locality, 1. 



Roumania : Bustenari, Prahova, 1. 

 . Switzerland : Meiringen, Bern, 1. 



Remarks. — Though its smaller size is the most obvious 

 character of this species as compared with N. noctula, the 

 bicolored fur, the different relative sizes of the upper incisors, 

 and the more abrupt convexity of the mandibular incisor series 

 would by themselves be quite sufficient to distinguish it. 



