224 EUROPEAN REPTILES. 



conscious of the alarm which fishes feel at any shadow, it 

 is careful never to hunt for prey except in the absence of 

 the sun. But in the pools we have described the water is 

 so muddy that no shadow can be reflected by it ; and the 

 fish, moreover, have no possible means of escape. As if 

 aware of these facts, the heron does not hesitate to fish in 

 them even in the full glow of the sunlight, — an interest- 

 ing illustration of its innate and pre-ordained intelligence. 



REPTILE LIFE IN TEMPERATE EUROPE. 



It is almost needless to say that the Amphibia are well 

 represented in Europe. Frogs and toads abound in all 

 marshy places ; but they do not attain to the dimensions 

 of the North American bull-frog or the hideous pipa of 

 Brazil and Surinam. Great Britain has only two species 

 of frogs and the same number of toads — the Common 

 Toad and the Natter-Jack. Of the tree-frogs there is one 

 European species — the Hyla arborea — whose webbed feet 

 are provided with little cushions at the points of the toes, 

 forming a kind of sucker, by means of which they can 

 force out the air from under their feet, and, aided by the 

 atmospheric pressure, adhere to the under surface of the 

 smoothest leaf, in the same way as a fly clings to the 

 ceiling of a room. To Europe also belongs the Eatable 

 Frog, which is employed as an article of diet in some 

 parts of France. 



Coming to the Chelonians, we find that the land tor- 

 toises are by no means uncommon in Europe. In all the 

 countries of the Mediterranean basin is found the Common 

 Tortoise — Testudo Groeca — which measures about a foot in 



