13 A T R A C H 1 A. 



309 



tne time that they are in progress, being merely 

 cast upon the waters, and abandoned to the ele- 

 ments. They are abandoned to these, too, at the 

 place where their action is the most powerful and the 

 most varied ; for a little elevation in the air, or a little 

 depression under the surface of the earth, would 

 exempt them from much of the variable action of the 

 weather. 



No other vertebrated animals thus leave their eggs 

 wholly unprotected, or place them on the plane of the 

 greatest action of the weather. But the free air of 

 the atmosphere, the action of light, arid the water, 

 are required for the development of the batrachia ; 

 and in order to enjoy all these, they must, of course, 

 abide the viscissitudes of the weather. But it appears 

 that they are tempered to the trial which they must 

 thus endure; and though in cold places they are often 

 frozen quite solid, it does not appear that they are 

 thereby injured ; for one may see the spawn im- 

 bedded in solid ice, and yet when the season comes 

 round, the water of the same pool or ditch swarms 

 with tadpoles. Some of the other species, as, for 

 instance, the common toad, are much more retiring 

 in their habits than the frog, and consequently much 

 more obscure in all their economy. Among them, in 

 the adult state, the principle of life is remarkably 

 tenacious a.s well as sluggish ; and we have instances 

 of their bein^ inclosed in growing trees and yet con- 

 tinuing to live. They also appear to require much 

 more action of the sun to call them from their sea- 

 sonal repose than the frogs do ; and yet they even 

 more habitually avoid the sun's direct action. They 

 do not make their appearance till the earth has been 

 heated by the action of the sun ; und not then, till it 

 has been, in some measure, cooled again. Still evenings 

 after summer showers, or dewy evenings after sultry 

 days, and when the sun has a little passed the summer 

 solstice, are the favourite times for these harmless but 

 generally hated animals. They also breed later in 

 the season than the frogs, and do not deposit their 

 eggs or spawn so decidedly in the water ; but still 

 humidity appears necessary for its development, as it 

 is often found in showery weather where water has 

 been partially stagnant, in the form of stringy masses 

 of gelatinous or gluey matter, which are, by the rus- 

 tics in some parts of the country, known by the odd 

 name of" fallen stars." What may have given rise 

 to this absurd name, and to the more absurd belief 

 on which it is founded, it is not easy to say. Toad 

 spawn does certainly appear as late in the season as 

 that at which, in the colder parts of this country at 

 least, the meteors called " .-hooting stars" arc not 

 unfrequent in the evenings ; and as these meteors are 

 very generally followed by rain, it is not unnatural 

 that the meteor and the spawn of the toad should be 

 observed in succession ; but why the one should 

 have come to be identified with the other, it is not so 

 easy to determine. 



The batrachia have not only this double action- 

 the action both of water and of atmospheric air, in 

 bringing them forward in the egg state, but they 

 have a double life afterwards, or, more strictly speak- 

 ing, they have two successive lives a first one in 

 the water, and breathing that fluid ; and a second one 

 in which, whether on the land or in the water, they 

 breathe air. The last of these lives, or states of 

 existence, must, however, be regarded with some 

 exception or explanation ; tor there are some genera 

 which retain both sorts of breathing apparatus, and 



thus are true amphibia, and indeed the only known 

 animals which, in a physiological point of view, merit 

 that appellation. 



Every one must be familiar with tadpoles, or frogs 

 in their first or aquatic state of existence. They 

 are of a dusky-blackish colour ; oval in the body, 

 with long fleshy tails compressed laterally, and fringed 

 with a sort of fin. Other than this tail they have no 

 organ of motion, and as the whole of their bodies do 

 not work so well in swimming as those of fishes, it 

 costs them much wriggling of the tail in order to get 

 along. When in this state their mouth can hardly 

 be said to consist of jaws, but rather of two horny 

 mandibles, forming a sort of beak. In this state they 

 are very voracious, as is generally the case with insects 

 in their larva state, or in that state in which they 

 come immediately from the egg ; and they eat indis- 

 criminately animal and vegetable matters. How far 

 they are able to go in the way of killing prey has not 

 been clearly ascertained ; but they can contrive to 

 nibble with their mandibles till they pick the bones 

 of a little fish perfectly clean. 



While they are in this state they breathe water, 

 and are incapable of breathing air. Their gills are 

 placed on the sides of the neck, supported by arches 

 of cartilage, and having their entrance from the 

 mouth, but without any gill-lid to the openings for 

 the escape of the water. Thus, though they breathe 

 water, their breathing is not exactly similar to that of 

 fishes of any kind, though it approximates more to 

 that of the cartilaginous than of the bony fishes. In- 

 deed, it is toward the cartilaginous iishes that the 

 batrachian reptiles approximate in all the aquatic part 

 of their economy. But they are less perfect water- 

 breathers than even these ; which would lead to the 

 conclusion that their breathing, and all the functions 

 are but slow even there, as the water ha.s no ingress 

 but by the mouth, and there is no peculiar apparatus 

 by means of which its passage through the gills can 

 be accelerated. 



Tadpoles are, in those places which are favourable 

 to their existence, a very abundant production of the 

 season, apparently as numerous in proportion to full- 

 grown frogs as the fry of fishes are to the full-grown 

 of these animals. The pools and ditches in which 

 they are bred also often get dry as the summer ad- 

 vances although frogs do not deposit their spawn in 

 the water which stagnates from an occasional shower, 

 and which is certain to be dried up before the ave- 

 rage season of the tadpoles being able to take to the 

 land, and escape. This last circumstance, whatever 

 may be the instinct which guides the parent frogs in 

 the choice of the water, is what we might expect, 

 because it is part of the general system upon which 

 nature acts. Wherever the egg is deposited, or how 

 completely soever it may be abandoned by the 

 parent, it is always safe in nature's keeping ; and upon 

 the average, the egg is always placed in that situation 

 in which it is most certain of being brought to matu- 

 rity, and the young most certain of being fed until 

 it undergo some change, or can otherwise shift for 

 itself. 



But still, though the spawn of the batrachia is 

 deposited in such a way as secures the continuance of 

 the race, the eggs and the tadpoles are, in the case of 

 the frog, so very numerous, that they must answer 

 some other purpose in the economy of nature ; for in 

 nature there is no selfishness, no production, which 

 exists for itself only. Also, in the case ot ihose 



