62 



VESPERTILIONID^— NYCTALUS 



The colour above and below is yellowish or golden, almost ochraceous, 

 brown, very little lighter on the under surface; the hairs are almost 

 unicoloured, the basal and concealed portions being only of a slightly 

 lighter shade. The wing and foot are dusky; the lips, ear, and 

 nose lighter. In the newly-born young, the wing and interfemoral 

 membrane, the ear, muzzle, foot, and tail are pigmented nearly as 

 deeply as in adults, but all those parts, including the forearm, which in 

 the adult are covered with hair, are of a dull flesh colour. The eyes do 

 not open until at least the twelfth day, and the hair, preceded by 

 pigmentation, begins to make its appearance when the bat is about a 

 fortnight old (Whitaker, in MSS.). After the hair has been acquired, 

 the young at first are darker than the adults (Forrest, in MSS.). 



I find no trace of seasonal variation or moult, but it is probable 

 that, as with N. leisleri, the coat is pale and faded in early summer, 

 and deepest and richest 

 in early autumn just 

 before hibernation. Old 

 males are said to possess 

 the brightest golden fur. 



The skull is typical of 

 the genus. It is character- 

 ised by a strong lambdoid, 

 but, as a rule, weak sagittal 

 crest ; there is much indi- 

 vidual variation in size and 

 proportions (Fig. 4, No. i , 

 p. 56). 



The teeth are shown 

 in Fig. 6. The inner upper 

 incisor is bicuspid in the 

 young, but adults lose the 

 small outer cusp. The 

 outer upper incisor is 

 much shorter than the 

 inner, but much broader in 

 transverse section at the 

 base: its crown is hol- 

 lowed out for the recep- 

 tion of the tip of the 

 lower canine. The lower 

 incisors are crowded and overlap, so that their broad crowns are oblique 

 and parallel to the jaw. 



Laver mentions an almost black specimen, and Norton others " pied 

 with grey, also with black, and sometimes a light colour round the 



Fig. 6.— Front View of Incisors and Canines of 

 Nyctalus tioctula (enlarged apd diagrammatic.) 



