ROrsETTUS LKACHT. 



27 



/>;(r/(K»s«'s.— Distiu^niished from all other species of the genus by 

 the combination of the following characters:— Frontal region of 

 skull between postorbital processes flattened; premaxillaries in 

 co)itact, but rarely co-ossiiied ; total length of skull 40-5-43-8 mm. ; 

 palate-ridges normally 4 + 3 + 1. Wings from back of first toe, 

 or interspace between first and second toe; pollex (with claw) 

 31 -35-5 mm.; second phalanx of third digit 50-5-60 mm. ; second 

 phalanx of fifth digit nearly always shorter than first plialanx ; 

 cars not attenuated at tip ; fur short. Forearm 89-99 mm. 



Skull. — Brain-case moderately deflected (compare E. lanosus and 

 Ji. cmgnlensis). rremaxillaries in contact in front, hut rarely, 

 even iii very aged individuals, co-ossified (compare li. (pgijptiacus 

 and R. nnr/oleiisis). Frontal region between postorbital processes 

 flattened (compare R. anr/olensis) ; region between orbits cora- 

 ))aratirely narrow, the width of the interorbital constriction in 

 fully adult specimens being almost always distinctly less than the 

 width of the postorbital constriction (compare R. cef/i/ptiacus). 

 Temporal crests uniting into a sagittal crest at level with root of 

 zygomata, but very often remaining separate throughout the life of 

 the individual. 



Teeth. — Upper incisors almost eiiuidistant, or the interspace 

 between i' and i' much less than between i* and c. Distance c-p' 

 equal to or larger than between i" and c. p^ small, equal in size 

 to i-. m' equalling or exceeding p' in length, m' rather less than 

 half the size of m\ — Lower incisors crowded. A broad interspace 

 between c and p,. p, in cross section from twice to four times the 

 size of a lower incisor, situated nearer to ihe canine than to p^. 

 m . m,, and ra , elliptical oval or almost elliptical in outline ; m.^ 

 somewhat smaller than m, ; m^ from two thirds to less than one 

 half the si/e of m.,. 



J'alate-ridgex.—'SoTmaih 4 + 3-|-l. Variations from the rule: 

 the fourth ridge in some individuals interrujited in the median 

 line (formula: 3 + 4 + 1); a 9lh, more or less indistinct, ridge 

 occasionally detectable (formula : 4 + 3+2). 



Ears. — Outer much more convex than inner margin; tip not 

 attenuated, broadly rounded off above (compare R. arabicus). 

 Antitragal lobe flatly rounded. 



Winqs. — Pollex with claw equal in length to four fifths of second 

 metacarpal (or equal to first phalanx of fourth digit). Second 

 digit equal to metacarpal of third digit. First phalanx of third 

 digit eijual to two tliirds of metacarpal; second plialanx only a 

 little shorter than metacarpal. Second phalanx of fifth digit, with 

 rare individual exceptions, shorter than first phalanx (compare 

 R. avr/olensis). Wing-indices, see anted, p. 20.— Notopatagium 

 semicircular in outline, naked ; lateral membrane inserted on end 

 of first metal arsal, or between first and second toe. 10-14 long 

 f.isciic in the lateral membrane, viz.. 2-3 postanconeal, 8-10 pre- 

 anconeal. 



7'(/(7. — From one half to three fourths the length of the hind 



foot. 



/.',„.._l.;;irs naked posteriorly, except at base. Face in front of 

 and below ev.s short-haired. " Ftir on back short, soft ; longer. 



