BAKBASTELLA 



265 



about as long as tibia, with small but evident terminal lobe and 

 posterior keel ; tail with extreme tip projecting beyond inter- 

 i'emoral membrane. 



Coluur. — General coloui' a very dai'k brown between the seal- 

 brown and vandyke-brown of Ridgway, the hairs everywhere 

 dark brown to extreme base, those of upper parts tipped with 

 light glossy wood-brown producing a sharply contrasted wash 

 throughout I'egion behind shoulders, those of undei'parts tipped 

 with a paler, more drabby brown, but without producing so 

 decided a contrast as on back, though the wash is usually evident 

 along middle of belly ; hairs on l)ase of under side of interfemoral 

 membrane pale ecru-drab or whitish smoke-grey nearly or quite 

 to base. Ears and membranes in dry specimens br-own, hardly 

 so dark as ground colour of body. 



Skull. — The skull, though lightly-built and small, scarcely 

 exceeding that of Myotis mystacinus in length, is rather deep and 

 robust, with unusually lai'ge bi'ain-case relatively to the short 

 rostrum. Dorsal profile abruptly convex over anterior half of 

 brain-case, then nearly horizontal to somewhat overhanging 

 occiput ; ventral profile nearly horizontal, the floor of brain-case 

 scarcely elevated above level of tooth-i'ow. Brain-case high and 

 inflated anteriorly, relatively low posteriorly, its lateral outlines 

 when viewed from above essentially as in the 

 species of Myotis, but less rounded and globular 

 posteriorly ; floor of brain-case with no special 

 peculiarities ; auditory bulke scarcely more in- 

 flated than in the small species of Myotis. 

 Interorbital region slightly constricted, its sur- 

 face flattened and not well defined from that of 

 rosti'um ; lachrymal ridges rather prominent, 

 especially at their lower extremities. Zygoma 

 nearly straight, scarcely bowed outward beyond 

 level of outer surface of brain-case. Ante- 

 orbital foramen relatively large, over anterior narbasteiia harha- 

 margin of m^. Rostrum short, its upper sur- stdlus. Nat. size, 

 face flattened-concave, deeply emarginate in 

 front by the unusual backward extension of the uppei- margin of 

 anterior nares, the posterior border of which is at level of ante- 

 orbital foramina, exposing anterior extremity of vomer. Palate 

 .short, noticeably concave both longitudinally and laterally ; its 

 anterior emargination small, extending slightly behind level of 

 middle of canine ; its posterior border slightly behind level of vi^, 

 double emarginate with short median projection ; mesopterygoid 

 space slightly wider than long. Mandible slender, with no special 

 peculiarities. 



Teeth. — In general aspect the teeth resemble those of Plecotus 

 (iHvitus, though they are throughout smaller and more slender. 

 1 ncisois botii above and below essentially as in Plecotus auritus 

 except that crown of outer upper incisor is nearly terete, and 



