372 Mr. (i. A. Boulenger on the Battachian 



\ I A . —Remarks on the Batvachian Genera Cornufer, Tschudi, 

 Platymantis, Gthr. } Simoniantis, a. n., and Staurois, Cope. 

 \U Li. A. Boulenger, F.R.S. 



(Published by permission of tin- Trustees of the British Museum.) 



In the March number o( these 'Annals' I have pointed out 

 some differences in the structure of the terminal discs of tin* 

 digits in the genus Rana, and endeavoured by their applica- 

 tion to the Papuan and Melanesian species to ensure a clearer 

 definition of these frogs and a grouping more in accordance 

 with their natural affinities. In proposing- the subgenus 

 Discodeles [or certain Indian and Melanesian frogs, the true 

 relationships of which 1 had failed to grasp before, T stated 

 that it leads to Connifcr, a genus previously defined as 

 differing front Rana in the free or very feebly webbed toes 

 and the complete union of the outer metatarsals by the 

 thickened integument, the web not penetrating between 

 them. In view of the state of things in the species grouped 

 under Discodeles, the definition is no longer sufficient, ami I 

 have had to consider whether Cornvfer should be treated as 

 a mere subgenus of Junta, or whether other characters, 

 justifying a generic separation, could be discovered. 



I have come to the conclusion, after examining a large 

 material, that, although unquestionably connected with Disco- 

 deles, these frogs can be sharply separated from Rana by 

 reverting to the view oi' Giinther (1858), that the species 

 with large digital discs (Cornufer, Tschudi, = Halophilus } 

 Girard) should be kept distinct from those with small discs 

 and practically free toes (Platymantis, Gthr.). 



The discs of Platymantis do not differ from those of liana 

 bufonifoi-nns, opisthodon, and guppyi, from which group the 

 genus may be derived, whilst those of Cornvfer, though 

 agreeing in shape with those of Rana beddomii and its Indian 

 allies, present this notable feature, that a transverse groove, 

 extending across the lower surface ami corresponding in 

 position with the horizontal limb ol' the T-shaped terminal 

 phalanx, is continuous with the crescentic or horseshoe- 

 shaped groove between the upper and the lower surface, thus 

 defining a hemispherical area within the disc, a feature which 

 is foreshadowed in the species of Rana (subgenus Hylorana) 

 separated by Cope under the mime of Amolops, in which a 

 more or less distinct transverse ridge or groove also corre- 

 sponds to the very long horizontal limb of the terminal 

 phalanx without actually joining the marginal groove. There 

 is, 1 feel sure, tto direct genetic connection between these 

 frogs ami Cornufer, as proved by the osteologieal characters 



