I. 



THE FROG (Rana temporaria and Rana esculentd). 



THE only species of Frog indigenous in Britain is that termed 

 the 'common' or 'Grass Frog' (Rana temporaria). On the 

 Continent, there is, in addition to this, another no less 

 abundant species, the hind-limbs of which are considered a 

 delicacy, whence it has received the name of the 'Edible 

 Frog ' (Rana esculentd). This species occurs only in a few 

 localities in Britain, into most of which it is known to have 

 been introduced. Unless the contrary be expressly stated, 

 the description here given applies to both species. The 

 Edible Frog is usually larger than the other, and is there- 

 fore more convenient for most anatomical and physiological 

 purposes. 



In the body of the Frog the head and trunk are readily 

 distinguishable; but there is no tail and no neck; the con- 

 tours of the head pass gradually into those of the body, the 

 fore-limbs being situated immediately behind the former. 

 There are two pairs of limbs, one anterior and one 

 posterior. 



The whole body is invested by a smooth moist integument. 

 The yellowish ground-colour of the skin is diversified by 

 patches of a more or less intense black, brown, greenish, or 

 reddish-yellow colour, and, in the Grass Frog, there is a 

 large, deep brown or black patch on each side of the head, 

 behind the eyes, which is very characteristic of the species. 

 The coloration of different frogs of the same species differs 

 widely; and the same frog will be found to change its colour, 



M. I 



