258 



CHIROPTEKA 



parallel with anterior border, and minute scattered tufts on other 

 parts of inner surface ; tragus simple, erect, about half as high 

 as conch, the anterior border straight below, slightly convex 

 above, the tip narrowly rounded, the posterior border faintly 

 concave above, distinctly convex below, greatest width (through 

 anterior base) equal to a little less than half length of anterior 

 border ; posterior basal lobe well developed though not large. 

 Wing broad, the fifth finger exceeding forearm by more than 

 one-third length of latter, the membrane thin and semi-trans- 

 parent, joining foot at base of outer toe ; third and fourth meta- 

 carpals equal, about 2 mm. shorter than forearm, fifth slightly 

 shorter than fourth ; leg slender ; foot about half tibia ; calcar 

 slender but sharply defined, equal in length to tibia and to free 

 border of interfemoral membrane, its distal termination marked 

 by a slight lobe, its keel obsolete. Tail extending about to point 

 of juncture of ears when laid forward, the extreme tip (about 

 1 ■ 5 mm.) free. 



Skull. — Among the European members of the order the 

 skull of Plecotus is noticeable for its large, rather low, smoothly 

 rounded brain-case, relatively small, weak rostrum, and much 

 inflated auditory bullae. Dorsal profile rising gradually from front 

 of nares to middle of anterior portion of brain-case, with slight 

 concavity at interlachrymal region, then falling gradually to 

 low, strongly convex, slightly overhanging lambda ; ventral 

 profile scarcely elevated posteriorly. Brain-case large but rather 

 low, the depth at middle only a little more 

 than half mastoid breadth, the general out- 

 line when viewed from above squarish with 

 rounded occipital projection and abrupt 

 g AaaawJiy anterior constriction, the surface smoothly 



rounded, with slightly indicated sagittal ridge 

 anteriorly and very low, short lambdoid crest, 

 the latter situated unusually close to upper 

 edge of foramen magnum ; an irregular area 

 in supramastoid region thickly sprinkled with 

 small vacuities ; base of brain-case smooth, 

 rh without special features, a narrow groove at 



Plecotus mmtus. each side of basioccipital ; auditory bulla 



Nat. stee. relatively larger than in any other European 



bat, its diameter about three times the 

 space between bullae. Interorbital constriction narrow, scarcely 

 hour-glass shaped, the anterior upper rim of orbit with narrow, 

 slightly projecting edge ; lachrymal region scarcely half as wide 

 as brain-case. Rostrum both narrow and short, the narial 

 emargination, though not unusually large, extending slightly 

 more than half way back to lachrymal level, its general outline 

 oval, sometimes flattened posteriorly ; dorsal surface of rostrum 

 with slight median crease, the sides evenly rounded ofi ; rostral 

 depth at front of orbit about equal to distance from orbit to 



