THE LESSER HORSESHOE BAT 



255 



females are found still virgin until their third October, in spite of the 

 fact that adult males have the organs in a seemingly functional con- 

 dition until May. 



Description: — In general appearance this bat resembles the pre- 

 ceding species, but its size is very much less, and its colour darker, 

 both in fur and membranes. , 



The ear (Fig. 2, No. 1 1 , p. 7) is rather more deeply sinuate on the 

 outer margin, the transverse sulci are less apparent (disappearing in 

 dry skins), and the basal lobe is larger in proportion. 



In the nose-leaf the horseshoe is less closely applied to the head, 

 the concentric rings, especially the median, are more conspicuous, 

 and the sella is cuneate, not fiddle-shaped, and has its summit 

 pointed. 



In the wing (Plate XVII., Fig. 3) the second phalanges of digits 

 three and four are less than one and a half times the length of the meta- 

 carpals. The fourth metacarpal is slightly the longest of the three. 



The general colour of adults is, above, 

 brownish "drab," with variations either 

 towards " wood - brown " or " Prout's 

 brown," the bases of the hairs being 

 everywhere " ecru drab " ; the underside 

 is "ecru drab," with variations towards 

 " drab-grey." 



The wing, ear, and foot are coloured as 

 in R. ferrum-equinum. 



As in the last species, young indi- 

 viduals are as large as their parents 

 by their first September, but are greyer, 

 being very nearly "mouse-grey" above, 

 with the bases of the hairs everywhere 

 "drab-grey." The upper side is clothed 

 with downy hair at birth (Whitaker). 



In the skull (Fig. 26) the auditory 

 bullae are so large that the basi-occipital is 

 very much narrowed between them so as 

 to become a mere bridge of bone. Some- 

 times the bullae are nearly in contact. 



The anterior upper premolar, though 

 small, is in the tooth-row, the upper canine 

 and posterior premolar being well sepa- 

 rated. In the lower jaw the anterior and posterior premolars are 

 usually almost or quite in contact, the central external, but there is 

 some variation in this respect. 



The individual variation of this species has not been studied in any 



Fig. 26 — Diagram of Teeth of 



Rhinolophus hipposideros, 



(i) Upper and (2) Lower Jaw. 



