OF FROGS, LIZARDS, AND SERPENTS. 



BOOK I. 



OF FROGS AND TOADS. 



'. frog and 

 days under 

 ion ; they 

 id what is 

 gs, like bladders, 

 ded with wind, and 



CHAP. I. 



OF FROGS AND TOADS I GENERAL. 



it? we emerge from the deep, tin first and 



most obvious class of amphibious animals that 



occur upon land are frogs and . These, 



wherever they reside, seem equally adapted 



for living upon land, and in tl e water, having 



their hearts formed i manner as to 



dispense with the assist;* of the lungs in 



carrying on tht? circ 



the toad, thr; -Fore, c 



water, without 



want but li 



wanting is 



which are < 



answer all the purposes of voir 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 frog 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. 



CHAP. II. 



OF THE FROG, AND ITS VARIETIES. 



I 



VOL. II. 



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 

 3 B 



