78 BOLKAY 



If we look back on the above tables as well as on the osteological 

 characteristics and description of the Chinese frog we shall find that, 

 owing to all its distinctive features R. chinensis can be placed near 

 to R. ridibunda Pall, and that neither R. esculenta nor var. lessonce 

 seems designated for a closer comparison with it. 



Up to now, the glandular folds on the back were alone considered 

 as easily distinguishable characteristic marks; I find, however, that 

 the most important amongst the outer distinctive features are: 

 the general shape of the head, color of vocal sacs, shape of spots on 

 the back and, finally, the formation of inner meta-tarsal tubercle. 

 The head is comparatively very narrow and the snout ends in a 

 very marked point. 



My experience is that we never meet with R. esculenta having 

 a similarly narrow head or pointed snout. Needless to say that in 

 that respect the Chinese frog differs still more from Rana ridibunda. 

 The vocal sacs are of a dusky grey and in that feature it quite re- 

 sembles R. ridibunda. 



As regards the spots on the back it differs very markedly from 

 esculenta, as already mentioned the spots on the back on some of 

 the specimens from China broaden in horizontal direction, giving 

 the back the appearance of being horizontally striped. On other 

 specimens from China the spots are entirely similar in form and dis- 

 position, to those of our esculenta. The spots on the specimens from 

 Japan present quite a different shape, extending, generally length- 

 wise on the back, the cross-bars dividing into spots on thigh and 

 tibia, in opposition to the Chinese specimens on which these cross- 

 bars invariably form an uninterrupted dark line. The Chinese 

 frog therefore, as regards the shape of its spots, could be said to 

 somewhat approach the typical R. ridibunda in which the spots 

 of the back frequently broaden horizontally. 



Finally, I consider the most important mark to be the inner 

 meta-tarsal tubercle not meaning thereby its proportions as do 

 Boulenger and his adherents but most especially taking into con- 

 sideration the differences manifested in its formation and its bio- 

 logical role. These differences separate insuperably Rana chinen- 

 sis from the group of either esculenta or ridibunda. As I already 

 remarked in the above description, the chief difference between the 

 meta-tarsal tubercle of Rana chinensis and that of esculenta and 



