78 REPTILIA. 



to their withdrawing under the skin, where they form the bran- 

 chiae. These latter are numerous small tufts attached to four 

 cartilaginous arches, placed on each side of the neck, adhering to 

 the hyoid bone, enveloped in a membranous tunic and covered by 

 the general skin. The water which enters the mouth, passing 

 through the intervals of the cartilaginous arches, makes its exit, 

 sometimes by two openings, and at others by one, situated either in 

 the middle or left side of the external skin, according to the spe- 

 cies. The hind feet of the Tadpole are very gradually and visibly 

 developed^ the fore feet are also developed, but under the skin, 

 through which they subsequently penetrate. The tail is gradually 

 absorbed. The beak falls and discloses the true jaws, which at first 

 were soft and concealed beneath the skin; and the branchicC are an- 

 nihilated, leaving to the lungs alone the function of respiration in 

 which they participated. The eyes which at first could only be dis- 

 cerned through a transparent spot in the skin of the Tadpole, are 

 now visible with their three lids. The intestines, which, in the be- 

 ginning, were long, slender, and spirally arranged, become short- 

 ened, and acquire the enlargements requisite for the stomach and 

 colon, for the Tadpole feeds solely on aquatic plants, and the adult 

 animal upon insects and other animal matters. Tadpoles reproduce 

 their limbs almost like Salamanders. 



The period at which each of these changes takes place varies with 

 the species. 



In cold and temperate climates, the perfect animal passes the win- 

 ter under ground, or in the the mud under water, without eating or 

 breathing, though if we prevent it from respiring during the sum- 

 mer for a few minutes by keeping its mouth open, it dies. 



Rana, Laur. 



Frogs, properly so called, have a long tapering body,- the hind feet 

 extremely long, strong, and more or less perfectly palmated; the skin 

 smooth; upper jaw furnished all round with a row of small fine 

 teeth and an interrupted transverse range of them in the middle of 

 the palate. On each side of the head of the male and below the ear, 

 is a thin membrane which becomes distended v.'ith air when he 

 croaks. These animals'leap and swim well. 



R. esculenfa,L.; Roesel. Ran. pi. xiii, xiv. (The Green Frog.) 

 A fine green spotted with black; three yellow streaks on the 

 back; belly yellowish. A common species in Europe in all 

 stagnant waters, and very annoying by its ceaseless nocturnal 

 clamour. Its flesh is a wholesome and agreeable food. The 

 female excludes her ova in bundles in the marshes, he. 



