THE YOUNG NATUBALIST. 



173 



efficacy has been subsequently augmented, since it enables its possessor to 

 obtain a greater variety of food. I call it protective development, because it 

 is a fact that frogs are eagerly sought as food by snakes, birds, and other 

 animals. 



The frog is decidedly more aquatic than the toad, arid is frequently found 

 in the water, in other than the breeding season ; in this respect,.also differing 

 from the newts, their allies. 



Frogs are never found far from water, and here again the extraordinary 

 muscular developments which give them their great leaping power come into 

 play, in their protective capacity, enabling them to swim and dive with 

 remarkable facility, and so escape many of their foes ; and being of further 

 advantage, in enabling them to capture their aquatic prey, such as the larvse 

 of the dragon-fly. Frogs are never seen in the winter months ; at the com- 

 mencement of hard weather, usually in October, they bury themselves in the 

 mud at the bottom of the ponds ; and any one who will take the trouble to 

 slouch a pit, during the month of January, may demonstrate this. It may 

 be a cold and somewhat dirty task, but who would allow personal discomfort 

 to interfere with his pursuit of truth ? Assisted by another member of our 

 society, Mr. F. W. Monks, I undertook this task in February of the present 

 year. Ice was still on the pond, but after considerable exertion, we succeeded 

 in taking several frogs, which were buried some six inches deep in the mud. 

 When placed in aquaria, they immediately buried themselves amongst the 

 small gravel at the bottom. I have often found them hybernating in the 

 mud in the bottom of ditches or cuttings in brickyards. As spring advances, 

 these sleepy creatures emerge, and may be seen in considerable numbers in 

 the vicinity of ponds and ditches ; and towards evening, when it is too dusk 

 to see them, their presence is made known by the sonorous croakings of the 

 males, who at this period are extremely amorous. Frogs usually breed in 

 the fourth year, and though their vocal efforts are scarcely so enchanting as 

 those of the nightingale, yet no doubt they are appreciated by the female, 

 who herself possesses only the power of emitting a faint squeak. 



Frogs live to be about 15 years old; and cast their skin several times each 

 summer, It is always cast in the water, and comes off piecemeal, apparently 

 giving the animal little or no trouble during the operation. When handling 

 a frog, we notice how cold and clammy it is, and if we use it roughly, we 

 find that it ejects what at first we might think urine, but is really limpid 

 water. If the skin becomes dry, the animal speedily dies ; for its pulmonary 

 respiration is not sufficient to maintain life, and this deficient power of the 

 lungs is supplemented by cutaneous respiration. As a fish dies when its gills 

 become dry, so a frog dies if its skin becomes dry. When a frog is in the 



