8 



ICNUD ANDERSEN 



(180) 



( 22 n N. , 33° E.) , is probably indistinguishable from the typical 

 form of acrotis, but I have as yet only seen immature examples ( v ). 



Rh. clivosus. — Rh. clivosus (-) differs from Rh. acrotis 

 in the following particulars: — 



The skull is larger, especially broader (compare the measure- 

 ments of the mastoid width, the brain-case, the zygomatic width). 

 p' 2 is present, situated external to the tooth-row; only in one very 

 aged specimen (Brit. Mus. no. o. 11. 4. 13), with the teeth 

 much worn down, it is absent; in all the specimens I have seen 

 of Rh. acrotis, including the immature individuals, p 8 is absent. 

 Upper canine and p 4 in close contact, as in acrotis. 



p a is absent in all the 5 specimens of clivosus to hand, the 

 teeth of which show very different stages of wear (from practically 

 unworn to much worn); but in one specimen some faint trace of 

 the alveoli is observable under a lens. So far as p 3 is concerned 

 there is, therefore, no noteworthy difference from acrotis, in which 

 I always found this premolar tracelessly wanting, irrespective of 

 the age of the individuals. 



Externally these two bats are difficult to distinguish. The horse- 

 shoe and sella may average a little broader in clivosus. 



Affinities. — Rh. clivosus is closely related to the Oriental 

 h'h. afflnis ( 3 ). The three species, Rh. affinis, clivosus, and 

 acrotis, illustrate three progressively higher stages in the devel- 

 opment of the dentition : — In affinis p 8 is external to the row 

 and extremely small; p 3 always in the tooth-row. In clivosus p., 

 has disappeared (at least in all the individuals I have seen); p' ! 

 is external to the row, exceedingly small, styliform, and sometimes 

 lost in aged individuals. In acrotis both p 3 and p 2 have disap- 

 peared, even in young adults. 



In the proportionate length of the metacarpals, as well as in 

 the lengthening of the second phalanx of the third digit, Rh. 



(') This fact should )>c borne in mind when comparing the measurements of 

 Rh. a andersoiii, as given in this paper p. 6, with those of Rh. a. typtens. The me- 

 tacarpals are probably not quite full-grown (distal epiphyses unossilied), but the 

 decisive characters of the skull and teeth are as in typical acrotis. 



(*) The following specimens of Rh. clivosus, from the collection of the British 

 Museum, have been examined: — 2 r? ad. (in ale); Dobar, near Iierbera, British 

 Somaliland; presented by Mr. E. Lort Phillips (95. 5. 28. 1-2). — rj 1 ad.. Q ad. (in ale); 

 Wagar, S. of Berbera, British Somaliland; collected by Mr. G. W. Bury (5. 11. 4. 13-14). 

 — rj 1 ad. (in ale); Harrar, Gallaland; collected by Mr. P. Feller; presented by Marquis 

 Q, Boria (5. 12. 15. 5). — Skulls of all (he 5 examples 



( ! ) On Rh. af/inis see Proc. Zool. Soc. London, 1905, II. pp. 101-100, pl. III. figs. 11-n. 



