180 



K\UD ANDERSEN' 



N. , oo^ E.) , is probably indistinguishable from the typical 

 form oi'acrotis, but I have as vet only seen immature examples (^). 



Rh. cUvosus, — Rh. cUvosus ("-) 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"^ is present, situated external to the tooth-row; only in one very 

 aged specimen (Brit. Mus. no. 5. 11. k. 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^ is absent. 

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



j)^ is absent in all the o specimens of cUvosus 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 pg 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 

 Rh. affinis (^). The three species, Rh. afflnis, clivosus, and 

 acrotis, illustrate three progressively higher stages in the devel- 

 opment of the dentition : — In afflnis pg is external to the row 

 and extremely small; p'' always in the tooth-row. In clivosus pg 

 has disappeared (at least in all tlie individuals I have seen); p'^ 

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

 lost in aged individuals. In acrotis both p^ and p"^ 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. Eh. 



(1) This fact should he home in mind when comparing the measurements of 

 Rh. a. andersoiii, as given in tliis i)aper p. 6, with those of Rh. a. typicus. The me- 

 tacarpals are prohahly not quite full-grown (distal epiphyses unossifled), hut the 

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



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

 Museum, have been examined: — 2 ad. (in ale); Do])ar. near Berbera, British 

 Sonialiland: presented by Mr. E. Lort Phillips (95. 5. 28. 1-2). — cj' ad., Q ad. (in ale); 

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

 — ^ ad. (in ale); Ilarrar, Gallaland: collected ]jy Mr. P. Felter; presented ])y Marquis 

 G. Doria (5. 12. 15. 5). — Skulls of all the 5 examples, 



(5; On Rh. affinis see Proc. Zool. Soc. London, 1905, II. pp. 101-106, pi. III. figs. 11-13. 



