Variation of the Edible Frog. 247 



\'. ridihunila 

 \ . saliurica . . 



1''. ti/pica 3-4 



V. IciSDwe 2 '-3 



\ . c/iiiiensis , , 



1. Width of tibia in length, — 2. liength of tibia ii; lenytli from snout 

 t;i vent. — 3. LeiiL'tli of tibia in length of foot (measured from 

 tarso-metatarsal articulation). — 4. Lung'th of metatarsal tubercle 

 in len;i:th of tibia. — o. Length of metatarsal tubercle in length of 

 inner toe. 



Bolkay gives tlio f'oilovving cliaracters fof tlistiiiguisliiiig 

 liis tliiee species : — 



Ii. esculeiita. Heels never meet ; tibio-tarsul articulation 

 readies space between tympaiiinn and posterior corner of 

 eye (?), or, at the utmost, space between anterior corner 

 ot eye and nostril ( cJ ) ; inner metatarsal tubercle large, com- 

 ])iessed, projecting, always longer than distance between it 

 and subarticular tubercle of tir.st toe. 



R. ridibunda. Heels always overlap ; tibio-tars.il joint just 

 i-eaclies back corner of eye ( ? ), or end of snout ( c? ) ; inner 

 metatarsal tul^erclc small, of flattish cylindrical form, not 

 very projecting, always shorter than space between it and 

 subarticular tubercle of first toe. 



Ii. chinensis. Heels never meet ; tiljio-tarsal joint reaches 

 posterior corner of eye or as far as space between anterior 

 c<;rner of eye and nostril; inner metatarsal tubercle very 

 large, projecting, compressed, liard and sharp, always a good 

 deal longer than it.s distance from subarticular tubercle of 

 tirst toe, frequently equal to length of first toe. 



The proportion of the tibia to the thigli, expressed by the 

 meeting or otherwise of the heels, is most useful for dis- 

 tinguishing the races, but it varies like most other characters, 

 and we must not sliut our eyes to exceptions to the rule. 

 To take R. ridibunda as an example, I now find that the 

 overlapping of the tibi?e is not so constant as I formerly 

 believed. Exceptions have already beeti noticed by ^leliely * 

 in specimens from Southern Hungary, and I find the 

 character to break down in 4: out of 13 examj)les from 

 Angora and in 3 from Damascus which have lately been 

 submitted to me by il. H. Gadeau de Kerville; besides, 

 I am now convinced that tlie var. fiusana, proposed by me 

 for specimens from Persia f, in which the tibiae simply meet, 



* Zicby's Zool. Forschuiigsr. p. 61 (1001). 

 t Anu. & Mag. N. H. (7) xvi. 1905, p. 552. 



