1905.] OF THE GENUS RHIKOLOPHUS. 1G9 



grej'ish " drab," lighter on the head and neck ; base of hairs '• ecru- 

 drab"; a strongly marked, dark brown horse-shoe patch ; under side 

 almost " ecru-drab " on throat and breast, very li^ht " drab " on 

 belly. 



(2) One (female, December-) ; teeth almost unA\'orn ; must be very 

 neai'ly of the same age as (1) : — Intermediate in colour between 

 (1) and (3), but nearer to (3). 



(3) Thi'ee aged individuals (females, Decembei-) ; teeth worn ; 

 two of them are at least 1| years old, the third (teeth very much 

 worn) still older : — Upper side, a shade of brown which might be 

 described as " mars-brown " with a pi'onounced tinge of '• drab " ■; 

 base of hairs light " eci'u-di-ab " ; scarcely any indication of a 

 horse-shoe patch ; under side light " wood-brown" with a tinge of 

 '• ecru-drab." 



In a sei'ies from the Hautes- Pyrenees (January) I find the 

 same differences in colour, but have not been able to verify the 

 comparative age of the individuals b}' means of the skulls. 



Three skins from Minorca (spring) are like the aged Swiss 

 individuals or, if anything, a trifle lighter. The teeth are worn, 

 showing the animals to be, probably, at least about two years old. 



Skins of aged individuals from England ai'O indistinguishable 

 from Swiss specimens of a like age. A very yoinig (not full- 

 gi-own) example from Somerset is quite like the younger (greyish- 

 drab) individuals from Switzerland. 



As a general conclusion : young individuals are, bioadly 

 speaking, dark grey, old individuals brown ; the colour of the 

 young animal is retained, at least in some individuals, till 

 December, beyond the time when the epiphyses of the metacarpals 

 have become ossified. For those who have an oppoi'tunity to 

 watch these Bats in the caves during the winter, it would be an 

 object of some interest to ascertain how the colour-change is 

 effected, by a moult or by a recolouring of the hairs. 



Skull. The essential characters as in Rh. affinis, the general 

 shajje hardly different, but as a rule, of course, the skull is larger. 

 The four anterior swellings are slightly more differentiated ; the 

 median ones almost circular in outline, the lateral ones oblong. 

 Chief character : the much longer palatal bridge : very nearly ^ 

 the leng-th of the maxillar tooth-i-ow, a little more or less, but 

 never so short as \ the tooth-row (as in affinis). 



Dentition, p,^ external and exceedingly small, or, very often, lost, 

 also in younger individuals, p, and p^ in contact, p^ completely 

 external, extremely small, not rarely lost, also in younger 

 individuals. Upper canine and p* not only in contact, but their 

 cingula, as a rule, considerably overlapping each other (the cingula 

 of p'* being external to that of the canine). 



Measurements. On p. 115. 



Distribution. From S. China and Jaj)an, through the Himalayas, 

 the Mediterranean Subregion (exclusive of Egypt), and Central 

 Europe to S. England. 



Geographical races. There are, at least, six forms of Rh. ferrum- 



