484 



THE NATURE BOOK 



or a baby of his own species — the frog or 

 toad flings not only his tongue but him- 

 self. Having engulfed as much as his 

 mouth \\iU hold, he helps the remainder 

 in with his hands. 



Frog and toad tadpoles develop, like 

 those of the newt, from eggs laid in the 

 water. In the case of the frogs, each 

 egg has a separate layer of mucus round 



TOAD SPAWN, AX^HICH IS LAID IN ROPES OF MUCUS 



it ; and a clutch of eggs, w^hen the mucus 

 has taken up as much water as it will 

 hold, constitutes the familiar frog's-spawn. 

 The Grass Frog lays from i,ooo to 2,000 

 eggs at a sitting, the Water Frog from 

 5,000 to 10,000, the Common Toad from 

 2,000 to 7,000, and the Natterjack from 

 3,000 to 4,000.* Toads expel their eggs 

 in two ropes of mucus, which in the 

 Common Toad are from ten to fifteen 

 feet in length and in the Natterjack from 

 five to six feet. The latter has the smallest 

 tadpoles — about an inch long including 

 their tails, and the Water Frog the largest 

 — about two and a half inches long. The 

 piebald eggs of the latter, however, are 

 very small. The Grass Frog is the earliest 

 to breed, then come the toads, and the 

 Water Frog is last of all. 



In the adult state our four British 

 species are easily cUstinguishable, but it 

 should be pointed out that the Water 

 Frog (the name is preferable to Ethble 

 Frog, for the Grass Frog is equally succu- 

 * Gaduw. 



lent, though there is less of him), has 

 rather a dubious claim to be considered 

 indigenous. His claim, however, to be 

 completely naturalised, on the ground of 

 having bred in the same locality for 

 upwards of seventy years and in other 

 localities at intervals during the same 

 period, can hardly be disputed. The 

 variety Lessonae of the Water Frog (Mr. 



Boulenger recognises 

 four distinct races) 

 was first observed in 

 the Fen districts about 

 1830, and is still abun- 

 dant in Nor folk. About 

 ten years back several 

 Turkish specimens 

 broke loose in the 

 neighbourhood of my 

 home in West Kent, 

 and seemed to hold 

 their ground for several 

 seasons. In recent 

 years, however, I 

 have neither heard 

 them, nor heard of 

 them. The chase of 

 the hibernating frog 

 is so well organised 

 in the immediate 

 neighbourhood of the 

 metropolis, that for a continental Water 

 Frog to have a fair chance of survival 

 he must be taken some distance afield ; 

 if possible to private ground, for his voice 

 bewrays him, and the laboratories wel- 

 come him gladly. 



The shape and size of the Water Frog 

 are distinctive, and the most remarkable 

 feature he possesses — the twin vocal sacs 

 which Ixilge as he croaks with closed lips 

 from slits on either side of his mouth — can 

 be seen in the illustraticm on page 483. As 

 a vocalist he is by far the most notable of 

 our amphibians. His everyday note is a 

 drawling quack, but his special love-song 

 is the •' Brck-ek-ek-ek-ex — ko-ax, ko-ax" of 

 Aristophanes, which is familiar to every 

 schoolboy. The first few notes of this are 

 a preliminary sigh, the finale a pc-ean of 

 satisfaction. Next to the Water Frog in 

 song comes the Natterjack. He has only 

 one vocal sac, deeply pigmented, and 

 situated on the floor of his mouth. Air 

 is forced into this through slits l^eneath 

 his tongue, and the resultant melody is 



