248 Mr. G. A. Boulengcr on the Races and 



does not deserve to stand. These exceptions, occurring in 

 Asia, cannot be disposed of by an appeal to hybridity, as in 

 the case of critical specimens from Germany and Austria- 

 Hungary, where the var. ridibunda occurs side by side with 

 the typical form, which fact would render such an assumption 

 legitimate. From what I have myself observed in the Spree 

 lakes near Berlin, I have no doubt the two forms cross in 

 exceptional cases, notwithstanding the asyngamy which 

 maintains their segregation when living together, but w.: 

 have no practical means of discriminating between such 

 mongrels and truly annectant specimens. 



I may mention that the tibise feebly overlap in one 

 specimen of the typical form from Warsaw and in another 

 from Mestre. As regards the R. chinensis, I am greatly 

 surprised at Bolkay's statement, which is contrary to the 

 descriptions by myself and by Wolterstorff*, although 

 supported by the description of one specimen by Stejneger "j"; 

 the two first authors agree as to the heels meeting, Wolter- 

 storff even adding that they sometimes slightly overlap ; 

 the only specimens in which I find the heels not to meet are 

 from Kobe, Japan (two), and Pekin (6 out of 26), and they 

 must be regarded as exceptions to the rule. 



Although the hind limb is often shorter in the female than 

 in the male, this is by no means generally the case; I can 

 show no end of female specimens of the var. ridibunda from 

 Central and Eastern Europe and Asia in which the tibio- 

 tarsal articulation reaches beyond the eye, and even one, 

 from Alemtejo, Portugal, in which it extends to the tip of 

 the snout — that is, farther than in most males ; in a male 

 from Corunna it reaches the eye, whilst in a female of 

 identical size and locality it reaches between the eye and 

 the nostril. 



Bolkay's way of expressing the length of the inner meta- 

 tarsal tubercle as compared to the inner toe originates from 

 me, with certain reservations, however J, but I have aban- 

 doned it long ago, having found many specimens of the 

 typical form in which the tubercle is not longer than its 

 distance from the subarticular tubercle of the first toe, whilst, 

 on the other hand, it may be as long in specimens of the 

 var. ridibunda. 



Ir has been pointed out by Bedriaga §, Wolterstorff, and 

 Bolkay that the usually highly developed, .shovel-shaped 



* Abb. Mas. Magdeb. i. 1906, p. 140. 



f Herp. Japan, p. 97 (1907). 



% Proc. Zool. Soc. 1885, p. G68. 



§ YViss. Ues. Przewalslri Exped., Zool. iii. i. p. 15 (1899). 



