308 



BATRACHIA 



that temperature to be more uniform than could be 

 obtained in the open air, with even the common alter- 

 nation of day and night. In all of them there is a 

 natural provision for the bringing about of those cir- 

 cumstances which are necessary for their development; 

 an animal action, opposed to or counteracting the 

 natural operations of inorganic matter, and the only 

 measure that we have of this animal action, is the 

 extent to which it counteracts them. We find that 

 gradually diminishing in the order in which we have 

 taken the animals, till we come to that of the reptiles, 

 which is simply burying their eggs in the earth ; and 

 when we look at the animals themselves, we find a 

 corresponding diminution in the development of life, 

 and the energy of all its functions. Some of the 

 saurian reptiles are remarkable for their agility ; but 

 it is known that most of them, and it is probable 

 that all, spend no inconsiderable portion of their time 

 in a state not merely of ordinary sleep, but of dor- 

 mance; that, whether the winter to which those 

 powers of activity yield be the natural winter a 

 season of cold or whether it be deluging rain or 

 burning drought, they all, to some extent or other, 

 hybernatc, and during that time, the functions of life 

 in them are very nearly suspended. 



But in their hybernations, animals pass to the place 

 of their birth, or to one bearing an analogy to it ; and 

 there is not, in all the races which have been men- 

 tioned, a single instance of one which hybernates in 

 the water. The alligators and water tortoises make 

 the entrances of their retreats often under the surface 

 of the water ; but the chamber of their repose is always 

 above the height of ordinary floods. They received 

 their animation upon the land, and it is upon the land 

 only that they appear to be capable of bearing these 

 lo^g pauses of its action. 



But when we come to the batrachian reptiles, we 

 find the beginning of life and the powers of its action 

 in a new element. We find, at the same time, less 

 animal action in the development of the egg, and a 

 simpler and less energetic organisation resulting from 

 it. There are no doubt differences of degree in the 

 different genera which make up the batrachia ; but 

 a kind of action, structure, and economy, and even 

 of locality, is common to them all. Generally speak- 

 ing, they are developed in the water; and if there are 

 any exceptions, it is only the damp earth instead of 

 the absolute pool. 



Yet though water is, thus, an element in the deve- 

 loping of the batrachian reptiles, they are not children 

 of the waters in the same sense or to the same extent 

 as the fishes. They come not from the depths ; and 

 the eggs which produce them are not aerated by air 

 derived from the water, as is the case with the spawn 

 of fishes, but by air derived from the atmosphere, 

 as in that of the other orders of reptiles. 



Among the fishes, we find the spawn deposited at 

 different depths. The bottom fishes lay it deeper 

 than those which play through the waters and find 

 part of their food at the surface. The carp family do 

 not seek the shallows as the salmon do ; and eels are 

 produced still deeper than carp. But in all true fishes 

 there is some depth of water over the eggs when the 

 action of life begins in them ; for those which are 

 committed to the' sea and float there, are, in general, 

 <*jore developed ere they are so committed, than the 

 eggs which are buried in the sand or glued to the 

 stones ; and besides, they do not " float out," till they 

 float as the empty tunics out of which the young 



animals have escaped as in what arc called the 

 " purses " of sharks and rays. If the oviparous animal 

 breathes water through life, the egg is also aerated hy 

 means of water when it is in a state of development ; 

 and the spawn of no fish can be quickened and ma- 

 tured in dry air any more than the egg of an oviparous 

 land animal can be hatched in the water. The proper 

 distinction is not land and water animals, but animals 

 which breathe the free air, and animals which breathe 

 through the medium of water ; and, with the exception 

 of the batrachia, all the vertebrated animals are, from 

 the first action of life in the germ to the last moment 

 of their living existence, true and constant to the one 

 or the other of these. The degree differs, for many 

 air animals seek their food in the water, and some 

 water animals pass part of their time in the air ; but 

 still, with the exception of the batrachia only, the 

 vertebrated animals all continue as they begin ; and 

 egg or animal, is equally deprived of life, if exposed 

 to the wrong element for a longer time than it can 

 exist without breathing, or being acted upon by that 

 element which is natural to it. 



So also, in all these there is no change of form at 

 any stage. There are certain parts of all animals 

 which are not required in the infancy of their lives, 

 and those of course are not then developed ; but the 

 animal is substantially the same from the time th;tt it 

 comes out of the egg till its final dissolution. 



Thus we have, independently of the ordinary clas- 

 sification of natural history, two grand divisions of 

 vertebrated animals: those which cannot live with- 

 out air, and those which cannot live without water. 

 Intermediate between these, we have the batrachia, 

 partaking of the characters of both ; and although 

 more decidedly reptiles than any thing else in the 

 systems of vertebrated animals, as at present arranged, 

 yet perhaps requiring, in a perfectly natural system, 

 to be formed into a separate order as should also 

 be the case with the marsupial animals, though even 

 these, in their general economy, do not stand so dis- 

 tinctly alone as the batrachia. 



The batrachia may be said to be productions of the 

 surface at which the air and the water meet ; though 

 as no animal can live in a mere surface, they find 

 their food in the one or in the other, or in both alter- 

 nately. In all those, of which the mode of produc- 

 tion is known, the spawn or eggs are committed to 

 the water, or to some humid surface, where they 

 have the advantage of the action of water. Bu. f they 

 " float out," and have the action of the air at the 

 same time. We are best acquainted with the spawn 

 of the common frog ; and that is never deposited in 

 deep water, in running streams which have much 

 current, or in fountains which flow clear and transpa- 

 rent from great depths in the earth, and, conse- 

 quently, with uniform temperature, or little affected 

 by the state of the weather. Pools and ditches, 

 in which the water is shallow, and which are tangled 

 with weeds in the season, or which otherwise show 

 that they are under the influence of the sun and the 

 atmosphere down to the very bottom, are the 

 places which the frogs select. There the eggs, float- 

 ing in the water certainly, but still with one side 

 of them exposed to the air, abide all the vicissitudes 

 of the season. They are pelted by the rain at one time, 

 heated by the rays of the sun at another, frozen at a 

 third ; and all these often alternately within a very 

 short time. They are thus exposed, too, without any 

 preparation by the parent animals, or any care during 



