PRIMARY DIVISIONS OF THE AMPHIBIA. 85 



function of atmospheric respiration, acquiring limbs 

 which are formed for leaping on land with great strength 

 and agility, and manifesting the most voracious car- 

 nivorous appetite, will not only excite feelings of the 

 deepest admiration, but necessarily lead to the inves- 

 tigation of the laws by which such extraordinary 

 changes are governed, and of the relations which they 

 bear to the theory of continuous affinity before alluded 

 to, no less than to that of progressive developement 

 through the whole of the animal kingdom." * 



(90.) The general peculiarities of this class, small 

 indeed in its numerical amount, but characterised by se- 

 veral remarkable circumstances, may be thus stated, in 

 reference to their distinction from fish and reptiles. The 

 skin is soft and naked, being destitute of either scales 

 or plates ; and nearly all undergo metamorphosis, the 

 young respiring by external branchia, and the adult by 

 internal lungs. With the exception of the frogs, they 

 have much of the form of lizards, with in general four 

 feet, and a lengthened tail. 



(91.) Passing over the various artificial arrangements 

 of this class, as unimportant to the paramount object of 

 our volume, we rejoice in being able to avail ourselves, 

 in this part of our undertaking, of the labours of one 

 of the most eminent erpetologists in Europe ; who, 

 thoroughly impressed with the truth of that circular 

 arrangement, which, if it pervades one class of animals, 

 must necessarily pervade all, has distributed the Am- 

 phibia in accordance with such a series ; and we deem 

 his labours so successful, that we shall not venture to 

 hazard the least alteration of our own. In a valuable 

 work not particularly devoted to Zoology f. Professor 

 Bell has arranged all the amphibians yet known under 

 the following orders: — 1. AmpMpneurta contains the 

 sirens and proteans ; 2. Anoura, comprehends the 

 frogs and toads ; 3. Urodela includes the salamanders ; 



* From the author's beautiful History of British Reptiles, p. 72,73. 

 t The EncyclopEedia of Anatomy and Physiology, part i. p. 91. 



o S 



