1920.] G. A. BoutENGER : Frogs of the Genus Rana. 



the distal third or fourth ; 

 Con- 



3. No tympanum ; outer metatarsals separated 

 omosternum entire. 

 h ,0'! ~ Nanorana. Gthr. Monotype : A', pleskel, Gthr., Kashmir and Thibet. 

 ' nected with the R. liebigii group through R. blan/oyciu, Blgr. 



B. Toes, often also fingers, dilated at the end, the dilatation, or disc, bearing a 

 crescentic or horseshoe -shaped horizontal groove. 



1. Outer metatarsals united or separated only in the distal third ; omosternum 



forked at the base. 

 (.m- Discodeles, Blgr. Type: R. g'lppyi, Blgr. 6 Indo-Malayan species, 3 Mcla- 

 nesian. Connected with Rana (/?. gntimiens group) ; leads to the Indo-Malayan, 

 Papuan, and Melanesian genera Coi-nufer, Tsch., and Plafymantis, Gthr. 



2. Outer metatarsals separated at least in the distal half ; omosternum entire. 

 ;, /2.3 Hylorana, Tsch. Type: R. erytlu-aea, Schleg. 58 South .Asian species, i 

 '' African, 5 Papuan and Melanesian. Completely connected with Rana {Ranae 



typicae) ; leads to the Indo-Malayan genera Sf an rois, Cope, and Simomantis, BIgr.i 

 II. Clavicles very slender, curved or directed obliquely backwards, widely sepa- 

 rated on the median line. 



A. Outer metatarsals united ; omosternum entire. 



Hilciebi-andtia, Nieden. Type; R. ornata, Peters. 7 species from Africa. 

 Burrowing forms. 



B. Outer metatarsals separated ; omosternum forked at the base ; distal pha- 



langes claw-shaped. 

 Ptychadena, Blgr. Type : R. mascareniensis, D. el B. 16 species from Africa, 



These two last subgenera are probably derived, as divergent 

 series, from a common ancestral type connected with the subgenus 



Rana. 



The following diagram expresses the relations between these 

 subgenera, as I conceive them. 



Ptychadena. Aubria. Hylorana. Discodeles. Nanorana. 



Hildebrandiia. 



Tomoptcrna. 



-Rana.- 



-Pyxiccphalus. 



Subgenus Rana, s. str. 

 Synopsis of the Species. 



1. Dorso-lateral glandular fold absent or, if present, not connected with the 

 supratemporal fold ; outer metatarsals separated at least in the distal half. 

 .\. Tympanum very distinct, smooth ; nasal bones in contact with each other, 

 with two exceptions '2 ; omosternal style forked at the base. 

 I. Inner metatarsal tubercle small but very prominent, pointed, digitiform ; 

 fingers pointed ; toes webbed to the tips ; male with external vocal sacs. 

 Vomerine teetli in strong oblique series in the adult ; 

 first finger longer than second ; toes pointed ; tibia 

 2 to 2| times as long as broad ; throat and belly with 

 granules and small warts ... ... .. R. hexadactyla, \.&ss. 



1 Cf. Boulenger, Ann. and Afag. A'. //. (g) I, 1918, p. 372. 

 * /?. microdisca and palavanensis. 



