OE FROGS, LIZARDS, AND SERPENTS. 



BOOK I. 



OF FROGS AND TOADS. 



CHAP. I. 



OP FROGS AND TOADS IN GENERAL. 



IP we emerge from the deep, the first and 

 most obvious class of amphibious animals that 

 occur upon land are frogs and toads. These, 

 wherever they reside, seem equally adapted 

 for living upon land, and in the water, having 

 their hearts formed in such a manner as to 

 dispense with the assistance of the lungs in 

 carrying on the circulation. The frog and 

 the toad, therefore, can live several days under 

 water, without any danger of suffocation ; they 

 want but little air at the bottom ; and what is 

 wanting is supplied by lungs, like bladders, 

 which are generally distended with wind, and 

 answer all the purposes of a reservoir from 

 whence to breathe. 



To describe the form of animals so well 

 known would be superfluous ; to mark those 

 differences that distinguish them from each 

 other may be necessary. The frog moves by 

 leaping ; the toad crawls along the ground : 

 the i'rog is, in general, less than the toad ; its 

 colour is brighter, and with a more polished 

 surface ; the toad is brown, rough and dusty. 

 The frog is light and active, and its belly 

 comparatively small ; the toad is slow, swol- 

 len, and incapable of escaping. The frog, 

 when taken, contracts itself so as to have a 

 lump on its back ; the toad's back is straight 

 and even. Their internal parts are nearly the 

 same, except that the lungs of the toad are 

 more compact than those of the frog; they 

 have fewer air-bladders, and, of consequence, 

 the animal is less fitted for living underwater. 

 Such are the differences with respect to figure 

 and conformation ; their habitudes and man- 

 ners exhibit a greater variety, and require a 

 separate description. 



VOL. It 



CHAR II. 



OF THE FROG, AND ITS VARIETIES. 



THE external figure of the frog is too well 

 known to need a description. Its power of 

 taking large leaps is remarkably great, com- 

 pared to the bulk of its body. It is the best 

 swimmer of all four-footed animals ; and na- 

 ture hath finely adapted its parts for those 

 ends, the arms being light and active, the legs 

 and thighs long, and furnished with very 

 strong muscles. 



If we examine this animal internally, we 

 shall find that it has a very little brain for its 

 size ; a very wide swallow ; a stomach seem- 

 ingly small, but capable of great distension. 

 The heart in the frog, as in all other animals 

 that are truly amphibious, has but one ventri- 

 cle ; so that the blood can circulate without the 

 assistance of the lungs, while it keeps under 

 water. The lungs resemble a number of 

 small bladders joined together, like the cells 

 of a honey-comb : they are connected to the 

 back by muscles, and can be distended or ex- 

 hausted at the animal's pleasure. The male 

 has two testiculi lying near the kidneys ; and 

 the female has two ovaries lying near the same 

 place ; but neither male nor female have any 

 of the external instruments of generation; the 

 anus serving for that purpose in both. Such 

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