Variation of the Edible Frog. 247 



1. 2. 3. 



\ . ridibunda . . 3-1 1*— 2\ 1-1} 



V.saharica 2f-3 2£-2§ 1-1 1 



F. %»'''« 3-4 1|-2J 1 V-li 



V. fesso«« 2i-3 2^,-21 1 i-l.i 



V. chinensis 2| -3| 2-2* lf-l$ 



1. Width of tibia in length. — 2. Length of tibia in length from snout 

 to vent. — 3. Length of tibia in length of foot (measured from 

 tarso-meta tarsal articulation). — 4. Length of metatarsal tubercle 

 in length of tibia. — 5. Length of metatarsal tubercle in length of 

 inner toe. 



Bolkay gives the following characters for distinguishing 

 his three species : — 



R. esculenta. Heels never meet ; tibio-tarsal articulation 

 reaches space between tympanum and posterior corner of 

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

 of eye and nostril ( <J ) ; inner metatarsal tubercle large, com- 

 pressed, projecting, always longer than distance between it 

 and subarticular tubercle of first toe. 



R. ridibunda. Heels always overlap ; tibio-tarsal joint just 

 reaches back corner of eye ( ? ), or end of snout ( $ ) ; inner 

 metatarsal tubercle small, of flatfish cylindrical form, not 

 very projecting, always shorter than space between it and 

 subarticular tubercle of first toe. 



R. chinensis. Heels never meet ; tibio-tarsal joint reaches 

 posterior corner of eye or as far as space between anterior 

 coiner of eye and nostril; inner metatarsal tubercle very 

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

 deal longer than its distance from subarticular tubercle of 

 first toe, frequently equal to length of first toe. 



The proportion of the tibia to the thigh, 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 shut our eyes to exceptions to the rule. 

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

 overlapping of the tibipe is not so constant as I formerly 

 believed. Exceptions have already been noticed by Me*hely * 

 in specimens from Southern Hungary, and I find the 

 character to break down in 4: out of 13 examples from 

 Angora and in 3 from Damascus which have lately been 

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

 I am now convinced that the var. susana, proposed by me 

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



* Zichy's Zool. Forschungsr. p. 61 (1901). 

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



