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* branchiae 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. They 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 thread of 

 gluten, which it seems to manage in the same 

 manner as some of the smaller slugs have been 



