158 DEVELOPMENT OF THE TADPOLE. 



As it is intended for the present to lead an aquatic life, its breathing apparatus 

 is formed on the same principle as the gills of a fish, but is visible externally, and 

 when fully developed consists of a double tuft of finger-like appendages on each side 

 of the head. The tadpole, with the fully developed branchiae, is shown at fig. a on 

 the accompanying illustration. No sooner, however, have these organs attained their 

 size than they begin again to diminish, the shape of the body and head being at 

 the same time much altered, as is seen in fig. b. In a short time they entirely 

 disappear, being dravn into the cavity of the chest and guarded externally by a 

 kind of gill cover. 



Other changes are taking place meanwhile. Just behind the head two little pro- 

 jections appear through the skin, which soon develop into legs, which, however, are not 



at all employed for progression, as the tadpole wriggles its 

 way through the water with that quick undulation of the flat 

 tail which is so familiar to us all. The creature then bears 

 b c the appearance represented in fig. c. 



Jik ^15k Jlk Presently another pair of legs make their appearance in 



^^Rk* iH ^^ front, the tail is gradually absorbed into the body not falling 



Mr* ^V^ ^n ^> according to the popular belief the branchiae vanish, and 



the lungs are developed. Fig. d represents a young Frog just 



/ \ before the tail is fully absorbed. 



C The internal changes are as marvellous as the external. 



) 1 When first hatched, the young tadpole is to all intents and 



purposes a fish, has fish-like bones, fish-like gills, and a 

 heart composed of only two chambers, one auricle and one 

 ventricle. But in proportion to its age, these organs receive 

 corresponding modifications, a third chamber for the heart 

 being formed by the expansion of one of the large arteries, 

 TADPOLES. the vessels of the branchiae becoming gradually suppressed 



and their place supplied by beautifully cellular lungs, formed 

 by a development of certain membranous sacs that appear 

 to be analogous to the air-bladders of the fishes. 



The Frog, contracted as are its intellectual powers, is yet susceptible to human 

 influence, and can be tamed by kind treatment. Mr. Bell mentions a curious instance 

 where one of these creatures became so completely domesticated, that it used to come 

 nightly from a hole in the skirting-boards where it had established itself, partake of food 

 offered to it by the members of the family, and even jump upon the hearth-rug in winter 

 in order to enjoy the warmth of the fire. A favourite cat, which inhabited the same 

 house, took a strange fancy to the Frog, and these seemingly incongruous companions 

 were to be constantly seen sitting together on the hearth-rug, the Frog nestling under the 

 soft warm fur of the cat. The Frog was, however, more than a year an inmate of the 

 house before it became domesticated, and for many months would retreat to its stronghold 

 when approached. 



Stories of so-called " showers of Frogs " are often seen in the papers, and as a general 

 rule are little to be credited, the solution of the supposed phenomenon being merely that 

 a shower of rain has induced the creatures to come simultaneously from their retreats. 

 There are, however, instances where credible spectators have seen them fall, and in such 

 cases the little creatures were probably sucked up by a waterspout, or even by a brisk 

 whirlwind, together with the water in which they were disporting, carried away for some 

 distance, and at last dropped on the ground, as is sometimes the case with sticks, stones, 

 and leaves, picked up by a passing whirlwind. 



The general colour of the common Frog is greenish yellow, or br,own, the same 

 individual often passing through all these colours in a few days. A long patch of blackish 

 brown or warm brown is placed behind each of the eyes, and it is yellowish white below. 

 There are no teeth in the lower jaw, and only a single row of very tiny teeth in the upper 

 jaw and on the palate. The ordinary length of the Frog is rather less than three inches, 

 aud the total length of the hinder leg is about four inches. 



