THE YOUNG NATURALIST. 



215 



six days later the fore legs were developed. Of the pools which I was ob- 

 ; serving, several dried up before the spawn had fully developed, and from this 

 we may learn the reason of the more rapid development of the young of this 

 species. 



Those individuals possessing an inherited tendency to mature more 

 : rapidly than the average, could alone survive and reproduce their species, in 

 the peculiar situations which the Natterjacks affect. As a proof that this 

 tendency to a more rapid development is hereditary, and not merely dependent 

 on the temperature or depth of the water in which they are laid, I may men- 

 tion that the development was equally rapid in the deepest and consequently 

 coolest pool. 



As an illustration of the enormous destruction of embryonic and larval life 

 in the circumstances under which Natterjacks exists, owing to the great 

 tendency of the smaller pools, in sandy places, to dry up in the summer 

 months, I found that one small pool, which had shrunk to about 6 feet by 4* 

 feet, by 6 inches deep in the middle, was positively black with tadpoles. 

 Having counted a few square inches, we estimated that the pool contained 

 at least 30,000 tadpoles; a few days later, this pool was completely dried up, 

 and all the tadpoles had perished. 



The ground colour of the Natterjack is usually light yellowish brown, 

 clouded with olive, and having a bright yellow line along the middle of the 

 back. The body is covered with tubercles, which are larger on the back, but 

 are smaller and more numerous on the other parts of the body. The ventral 

 surface is greenish white, marbled with black or dark grey. 



We will describe a pair of these toads as they appear in the breeding 

 season. 



The female is light yellowish brown, suffused with olive and speckled with 

 black spots or irregular bands, on the dorsal surface. The body is covered 

 with tubercles, those on the dorsal surface having a reddish tinge. The dor- 

 sal line is of a bright sulphur colour. As in Bufo vulgaris, there are two 

 large glands behind the eyes, which are prominent, having a black horizontal 

 pupil, with a gold rim. The ventral surface is covered with minute tubercles, 

 and is of a greenish-white colour, marked with black spots, which are less 

 numerous on the throat ; the markings on the sides of the abdomen are 

 larger and more of the nature of blotches. The legs are short, and formed 

 more for aquatic life ; the hind feet are palmated. The body is 2 \ inches 

 long; the hind leg %\ inches long; the fore leg is lj inches long, and the 

 feet not palmated. 



The markings of the male are like those of the female, but the ground 

 colour is darker. He is also much smaller ; the body being two inches long ; 



