BATKACIIIiUlS.- 



-EEPTILES.- 



-Batuachians. 



tliis prey they watch with great patience till it comes 

 ■wilhin their reach. They then dart upon it with great 

 velocity, shooting out the tongue in order to catch it 

 by means of the viscid secretion by which it is covered. 

 This fluid appears to retain the object seized, while the 

 two points of tlie bifurcation seenr to twist roinid it. 

 The prey once seized, it is sjieedily swallowed, the 

 animals pushing it into the oesophagus with the thumbs 



of their fore feet. In consequence of their feeding on 

 worms and mollusca, frogs are useful animals in gar- 

 dens, as they destroy great numbers of slugs and 

 worms, which are so hurtful in these places. Frogs, 

 having the toes of the hinder feet webbed, swim remark- 

 ably well in tlie water ; and on land their mode of 

 progression is by a series of successive short leaps^ 

 tig. 24. Those animals are generally found in mois'i, 



Fig. 24. 



Mouth and fore and hind feet of Rana Occipttalis— to show structure of toes and tongiie of the group Ranina, or Frogs. 



places, in the grass of meadows, and on the banks of 

 streamlets, into which they continually leap and dive. 

 In summer, during or after warm rain, they make their 

 appearance in our meadows in such vast quantities, that 

 many people have imagined that it had rained frogs. 

 This is an ancient belief, and is still in full credit in 

 the provincial parts of many countries of Europe. 

 Several of tlie old authors have mentioned this sudden 

 appearance of these creatm-es ; and Aristotle, in noticing 

 the phenomenon, calls the frogs so suddenly called as 

 it were into existence, diopdes {dluTirijg), or " sent 

 from Jove." The males of some species, especially 

 the Edible or Green frog, have two sacs called vocal 

 pouches, on each side of the throat, which in general 

 are only manifested externally by the swelling which 

 is produced in them when fdled with air. These ani- 

 mals have a peculiar and sonorous cry, louder and 

 stronger in the species with the vocal sacs, which is 

 known in this country by the name of croaking. It is 

 chiefly during rain in warm weather, and in the morn- 

 ing and evening, that we hear this noise, which must 

 be fixmiliar to every one. In autumn, when the sum- 

 mer heats are over, tliese animals appear to lose their 

 voracity, and cease to take food ; and when the cold 

 becomes more consiilerable, they protect themselves 

 from its rigour by siidiing into the mud of deep waters, 

 or by taking up their abode in holes on the banks of 

 streams and ditches. They sometimes assemble in one 

 place in such quantities as to cover the soil to the 

 depth of a foot, and thousands may thus be taken in a 

 few minutes. In this country they revive upon the 

 return of spring, and emerge from tlieir winter retreats 

 to recommence a life of activity and obey the grand 

 law of nature— the reproduction of their species. The 

 arrival of the season for this important function is 

 shown in the male by the appearance of a black wart 



on the fore feet, and the belly swelling. The male 

 frog leaps on the hack of the female, to whom he clings 

 by the aid of these warts on his fore feet. Dm'ing the 

 cohesion of the two sexes, which lasts for a consider- 

 able period, sometimes for fifteen or even twenty days, 

 the female commences depositing her eggs, which are 

 fecundated during their passage by the seminal fluid of 

 the male. When first expelled these eggs are globular, 

 black on one side, and whitish on the other. They 

 are enveloped in a glairy or glutinous transparent 

 mass, which serves for the nutriment of the embryo, 

 and swell greatly in the water after they are laid. 

 They are, in the case of the common frog of this 

 coimtry, deposited at the bottom of the water, and 

 then float on to the surface, and are left there to hatch 

 by the ordinary temperature of the atmosphere. The 

 number deposited at each laying is very great, as many 

 it is said as fronr six hundred to twelve hundred 

 annually. Swammerdam once counted eleven hundred, 

 and Montbeillard thirteen hundred, from one female. 

 The development of the young is more or less rapid 

 according to the temperature of the atmosphere. In 

 a few hours after its expidsion the egg begins to show 

 a slight change. At the end of about lifty hoiu's, when 

 the temperature is high, the embryo may be seen 

 within the egg, with the head well marked, the tail 

 somewhat elongated, and even the rudiment of the 

 membrane or web which is destined to form its fin ia 

 visible. The development then goes on gradually, till, 

 according to Professor Bell, in the ordinary temperature 

 of this country, at the end of a month the young crea- 

 ture bursts its shell and comes forth in the well-known 

 state of a tadpole. At this stage of its existence it is 

 blind and destitute of feet. It has a large head, a 

 globular belly, a long tail, and external gills by v/hich 

 it respires. It feeds solely on vegetable substances, 



