COMMON FROG. 99 



fore the time of exclusion, the young animals may 

 be perceived to move about in the surrounding glu- 

 ten. When first hatched, they feed on the remains 

 of the gluten in which they were imbedded, and 

 in the space of a few days, if narrowly examined, 

 they will be found to be furnished, on each side 

 the head, with a pair of ramified branchis or tem- 

 porary organs, which again disappear after a cer- 

 tain space. These tadpoles are so perfectly unlike 

 the animals in their complete state, that a person 

 inconversant in natural history would hardly sup- 

 pose them to bear any relationship to the Frog ; 

 since, on a general view, they appear to consist 

 merely of head and tail ; the former large, black, and 

 roundish ; the latter slender, and bordered with a 

 very broad transparent finny margin. Their mo- 

 tions are extremely lively, and they are often seen 

 in such vast numbers as to blacken the whole 

 water with their legions. 1 hey live on the leaves 

 of duckweed and other small water-plants, as well 

 as on various kinds of animalcules, &c. and when 

 arrived at a larger size, they may even be heard to 

 gnaw the edges of the leaves on which they feed ; 

 their mouths being furnished with extremely mi- 

 nute teeth or denticulations. The tadpole is also 

 furnished with a small kind of tubular sphincter 

 or sucker beneath the lower jaw, by the help of 

 which it hangs at pleasure to the under surface of 

 aquatic plants, &c. From this part it also occa- 

 sionally hangs, when very young, by a thiead of 

 gluten, which it seems to manage in the same 

 manner as some of the smaller slugs have been 



