173 



small longitudinal sulcus, more defined iu some specimens than iu 

 others, and especially large in immature animals (Plate XI. fig. 7). 

 The small nose-leaf scarcely exceeds the diameter of the nasal aper- 

 ture in height ; its general shape is broadly cordate, the broad ex- 

 tremity upwards and free, the front surface marked by a depression 

 above each nasal opening. 



In the form of the extremities and of the wing- and interfemoral 

 membranes very similar to Plecotus auritus, the antebrachial mem- 

 brane less developed, however. 



Wings from the base of the toes ; extreme tip of the tail free ; 

 calcaneum about three fourths the length of the tibia, with a small 

 postcalcaneal lobe about the centre. 



Muzzle very thinly covered with short hairs ; the inner side of 

 the ear-conch clothed with a few soft hairs, more thickly ranged 

 along the semicircular ridge, near the inner margin of the ear , 

 wing-membranes naked, except along the sides of the body. 



Fur remarkably similar to that of Plecotus auritus in colour and 

 quality, and, as in that species, variable in shade. In most speci- 

 mens the hairs on the upper surface are bicoloured, nearly black at 

 the base, the terminal half light or dark brown ; beneath, similar 

 at the base, but the extremities of the hairs much paler than on 

 the upper surface, very palo brown or even white. 



In the type of N. unicolor. Tomes, the fur is dark olive-brown 

 throughout on the upper surface, but this may be due to the spe- 

 cimen being immature ; other specimens from Tasmania agree in 

 the colour of the fur with those from Australia. 



The skeleton closely resembles that of Antrozous pallidus and 

 Plecotus auritus. The tympanic bidlse osseae are as large as in 

 Plecotus, and almost whoUy conceal the cochlea ; the bony palate 

 extends as far backwards as the middle of the zygomatic arch; 

 muzzle very short in front of the infraorbital foramen ; nasal and 

 frontal bones flattened, slightly concave ; sagittal and occipital crests 

 not prominent, more or less developed acccording to the age and 

 size of the specimens. 



The dentition is almost precisely similar to that of Scotophilus 

 temmincMi, the same shaped incisors close to the canines, the same 

 narrow last molar, the first lower premolar small and similarly 

 crushed in between the canine and second premolar. The ulna and 

 fibula are reduced to thin fibro-cartilaginouB threads ; tail of seven 

 vertebrae. 



Length (of an adult 2 ^°^ Port Essington), head and body 2", 

 tail l"-8, head 0"-8, ear 1" x 0"-6, tragus 0"-3 X 0"-15, forearm l"-8, 

 thumb 0"-3 ; third finger — metacarp. l"-55, 1st ph. 0"'65, 2nd ph. 

 0"-9 ; fifth finger— metacarp. l"-5, 1st ph. 0"-45, 2nd ph. 0"-35 ; 

 tibia 0"-8, foot 0"-35. 



The above measurements are taken from the largest specimen ex- 

 amined by the writer. Other specimens are often considerably 

 smaller, and the length of forearm appears to vary, in adult indi- 

 viduals,' from l"-6 to l"-8, the ears from 0"-95 to 1"-1. 



