4'.' 4 IMr. 0. Thomas on 



2. Hip:lier, divided in the centre by a iiotcli, the median 

 line ot which tends to be grooved, naked, and of a different 

 texture to the rest *. 



3. Much higher, the two divisions connected with eucli 

 other, and surpassed above, by a median, smooth, and naked 

 inembraiie, wliich is folded to form a Y-shaped groove on its 

 anterior surface f. 



There is, however, a nearly complete continuity of develop- 

 ment from one extreme to tiie other, so that the position of 

 individual specimens may occasionally be in doubt. 



The baculum in JSyctophilus has a broad stout bifid base 

 and a downwardly curved shaft, generally about 2^-3 times 

 the length of the breadth of the base. Its tip may be either 

 simj)le and slightly flattened, or bifurcate. 



The species are here taken geographically, beginning with 

 the west and passing first eastwards and then to the north 

 and north-west. 



1. Nyctophilus major, Peters. 



Abh. Ak. Berl. 1860, p. 125 (1861), ex Gray, Voy. Ereb. Terr. pi. xxi. 

 tig, 2 (plates prepared iu 184o, uot published till 1875). 



Size largest of the genus, a skull measuring 19'8 mm. in 

 greatest length; maxillary tooth-row 7'3. Bullae fairly 

 large, •4'3 mm. 



No spirit-specimens available, but the nose-leaf appears 

 from skins to be of the less-developed type. No bacula 

 seen. 



Ilah. "Western Australia. Ty[)e from Perth. Other 

 specimens from King (jeorge's Sound, Southern Cross, &c. 



Type. B.M. no. 44. 7. 9. 20. 



2. Nyctophilus geoffroyi, Leach. 



Trans. Linn. Soc. xiii. p. 78 (1822). 



N. australis, Peters, Abb. Ak. Berl. 1860, p. 123, plate (1861). 



Size small or medium. Ears proportionally large. Nose- 

 leaf of the most higiily developed type, as described under 

 3, above. Baculum with the normal broad bifid base and 

 simple sliglitly flattened tip. Bulla3 large. 



Three subspecies may be recognized : — 



* Dobson's figure (Catalogue, pi. xi. fig. 7) corresponds to this degree 

 of development, but is slightly exaggerated towards the third type. 



t Peters'e figure of Ni/ctojMhis australis (Abh. Ak. Berl. 1860, fl&te, 

 fig. 2) shows this leaf, but does not indicate the Y-shaped groove seen iu 

 the best-developed .specimens. 



