206 



CHIROPTERA 



the others) and extending nearly to point of elbow ; fifth finger 

 extending beyond elbow to a distance equal to less than one- 

 third length of forearm ; thumb short, its length about equal to 

 width of wrist ; membrane inserted at base of outer toe. Foot 

 about half as long as the short, robust tibia ; calcar considerably 

 longer than free border of interfemoral membrane, robust at base, 

 but tajjering rapidly and terminating without lobe, its keel well 

 developed, with evenly convex margin. Tail about as long as 

 body without head and 2^ times as long as tibia, the short 

 terminal vertebra free from membrane. 



Far and colour. — The fur is closely confined to the body, 

 showing no tendency to spread on membranes. On wing it 

 extends, both above and below, to line joining knee and basal 

 third of humerus ; lower surface of interfemoral membrane 

 essentially naked except at extreme base, upper surface furred, 

 nearly to middle. Colour of upper parts a uniform brown, in 

 most specimens nearly intermediate between the wood-brown and 

 cinnamon of Ridway but sometimes darker, with a strong tinge 

 of prouts-brown or raw umber, this especially noticeable in 

 immature specimens, though occasionally evident in adults ; 

 under parts essentially like back though slightly less dark ; hairs 

 everywhere slaty brown at base, those of upper parts with tips 

 darker than sub-terminal band, but not enough so to produce a 

 definitely tricolor effect. Ears and membranes blackish. 



Skull. — Notwithstanding its small size, less than that of any 

 other European bat, the skull is robust and heavily built as 

 compared with that of the small species of Mijotis. Dorsal profile 

 rising gradually from nares to lambda, with slight concavity in 

 interorbital region and slight convexity over middle of brain-case ; 

 occipital region scarcely produced backward except for a median 

 swelling between foramen magnum and lambda, 

 on each side of which a condyle is just visible 

 when skull is viewed from above ; ventral profile 

 nearly flat except for a slight upward bend pos- 

 teriorly. Brain-case ovate in general outline, 

 its region of greatest breadth distinctly behind 

 middle, its surface smooth or with faintly indi- 

 cated sagittal crest and lateral portion of 

 lambdoid crest ; greatest breadth of brain-case 

 Fig 34 noticeably exceeding that of rostrum and slightly 



Pipistreilus 'pipis- though evidently more than half greatest length 

 treiius. Nat. size, of skull ; floor of brain-case flat, without vacui- 

 ties ; a distinct groove between cochlea and 

 median portion of floor, this groove bounded antero-externally 

 by a slight though usually evident longitudinal ridge ; auditory 

 bull* moderately large, not peculiar in form ; interorbital region 

 broadly hour-glass shaped, its least breadth about equal to 

 breadth across roots of canines ; between constriction and ante- 

 orbital foramen the orbital margin is slightly but evidently 



