182 ANURA 



CHAP. 



to this habit it is called the " running toad " by the field- 

 labourers of Cambridgeshire. The skin is smooth, but less so 

 than in B. viridis, owing to the slightly more prominent warts ; 

 the parotoids are small ; a similar pair of glands lies on the 

 upper surface of the fore-arm and another on the calf. The 

 tympanum is rather indistinct. The ground-colour of the upper 

 parts is light brownish yellow, with a green tinge and scattered 

 green spots ; most specimens have a narrow yellow stripe along 

 the vertebral line and over the head. The under parts are 

 white, more or less speckled with black. The iris is greenish 

 yellow and speckled. The male, which is of the same size as 

 the female, very large specimens reaching 3 inches in length, 

 has a large subgular vocal sac, and develops nuptial brushes on 

 the first three fingers, but the first lacks the thickened pad of 

 B. viridis. 



The yellow vertebral line is sometimes absent in specimens 

 from the south of France and the Iberian Peninsula ; and since 

 these southerners are as a rule more handsomely marked, the 

 green being more pronounced and arranged in larger patches, 

 interspersed with red spots, they much resemble B. viridis. 

 Boulenger, who has paid especial attention to this vertebral 

 streak, which is a not uncommon design in various species of 

 different families, has made the interesting observation that the 

 streak has never been found in Danish and German specimens 

 of B. viridis, where B. calamita occurs also, while it is not 

 uncommon in B. viridis of Italy, South-Eastern Europe, Asia, 

 and North Africa, where B. calamita is not found. Lastly, he 

 remarks that in Eastern Asia, where neither B. viridis nor 

 B. calamita with such a line occurs, the same character is 

 assumed by some specimens of B. vulgaris. The only conclusion 

 we can draw from these facts is, that for some unknown reason 

 the streak is a desirable, but not necessary, possession, but that 

 it is not kept by two species in the same country, B. viridis 

 dropping it entirely where the typically streaked species, 

 B. calamita, also occurs. The breeding season does not begin in 

 England and Middle Europe until the end of April, in cold springs 

 not before May, but it lasts for several months. The males, con- 

 gregating in pools in great numbers, make a loud noise, each 

 individual uttering a rattling note which lasts a few seconds, 

 the repetition distending its bluish throat into the shape of a 



