330 



KANID^. 



Although so closely allied and living side by side in 

 many localities, these two species never appear to in- 

 terbreed. As in B. temporaria and B. arvalis, this is 

 probably to be ascribed mainly to the great difference 

 in the seminal elements, as mentioned on p. 77 of the 

 Introduction. 



Eggs. — According to Count Peracca, to whom I 

 am also indebted for eggs of this frog, the vitelline 

 sphere is blackish-brown, with the lower third white, 

 and measures If mm. ; the mucilaginous envelop is 

 also smaller than in B. agilis and B. temporaria, 6 or 



Fig. 120. 



7 mm. in diameter. The embryo, on leaving the egg 

 on the thirteenth or fourteenth day, is only half as 

 long as that of B. agilis. 



Tadpole (PI. Ill, fig. 6). — Intermediate between B. 

 temporaria and B. agilis. Width of mouth equalling 

 the distance between the nostrils and two-thirds the 

 distance between the eyes. Series of labial teeth f , 

 the second upper series very widely interrupted in the 

 middle, the third extremely short ; first lower series 

 very short, hardly half the length of the second ; 

 fourth interrupted in the middle. Beak as in B. tem- 

 poraria. Tail acutely pointed, twice as long as the 

 body, its depth one-third its length. Lines of muci- 

 ferous crypts very distinct, as in B. agilis. 



Brown above, whitish beneath ; caudal crests 

 whitish, dotted with dark brown, the upper with 

 some larger spots. 



