Anodonta, which are provided with hooks, hang on to the bodies of the bitterling, where Lhey 

 undergo their early development. 



River loaches (Cobiiis barbalula) live in clear running brooks and spawn in the spring. 

 When there is a storm, they come to the surface and with their snouts above water take in air. 

 This passes through the stomach into a chamber richly supplied with blood-vessels and here the 

 oxygen is absorbed. The stale air is got rid of through the intestine. 



Among the gentler kinds of fishes, is the blenny (Blennius fliivialilis), which is a freshwater 

 form of the marine family Blenniidae and is particularly found in the rivers of the south of 

 France. It is brownish in colour, being somewhat camouflaged. The flange-shaped crest in 

 the middle of the head is more emphasised in the males. In the same rivers there are gobies, 

 especially Gobiiis lota. Several other species live in the fresh waters of Italy. 



Millers-thumbs (Coitus gobio), which are found near mill-races and in trout-streams, have 

 a biology recalling that of the marine species of the family. The rather dull-looking females 

 have a whitish belly, whereas the colours of the males are intensified, the abdomen being grey 

 and striped with dark spots. As in the marine millers-thumbs, the eggs are put under heaps 

 of gravel or in crevices and the males stand guard. In spite of the formidable appearance given 

 them by their spines, they are harmless enough. Now and then, when some enemy has designs 

 on their spawn, they seem reluctant to give battle. Millers-thumbs normally live concealed 

 under stones, feeding on insects and small crustaceans. Great quantities of trout eggs are also 

 eaten by them. 



Not far from the millers-thumbs live burbot, freshwater members of the cod family. They 

 are fairly voracious and have an enormous fecundity, for their eggs are counted by millions. 

 These do not float like those of other gadids, nor are they attached. Like shad's eggs, they are 

 heavy and roll gently over the bottom at the mercy of the currents. Being a fish of northern 

 rivers, the burbot is rather rare in France. 



Beside these gentler kinds of fishes, the rivers contain predatory animals which are a great 

 menace to the other species, for they seize anything within their reach. The pike ( Esox luciiis) 

 is probably the most fearsome. With its long slim body and fins set well to the rear, it gives a 

 great impression of power. The large head with the broad, flat snout is reminiscent of that of a 

 crocodile. It is hardly a fish of rapidly-llowing streams, but is found in rather still waters, 

 which contain more of its prey, particularly the cyprinids. 



In one day a pike can eat a quantity of food equal to its own weight. He seizes other 

 fishes sideways-on and swallows them head first. When he hunts, and this takes up the greater 

 part of his time, he very often lurks among the weeds or else is quietly poised in the water looking 

 very like a piece of moss-covered wood. He is thus able to draw near his prey and he eyes them 

 without arousing suspicion. Suddenly he darts, devours his lish and disappears in a trail of 

 foam. His ravages are not confined to the typical river dwellers. Frogs taking the airon water- 

 lilies, rats prowling along the banks and waterfowl that may be washing and preening their 

 feathers are seized and devoured. Sometimes pike eat prey as large as themselves; the stomach 

 becomes much distended and digestion takes several hours, during which time they are quite 

 sluggish. 



During the breeding-season they have a poorer appetite. And from time to time they 

 become less voracious and eat rather little, this being put down to their gums being sensitive 

 while teeth are being replaced. Pike are polyandrous, one female accepting several males. She 

 stays quite still while these contenders closely beset her; then sends them off with a tlick of the 

 tail. But she allows them to make another approach. The eggs are laid at random and are in 

 no way cared for by the parents. Many of them are destroyed or eaten. 



Pike can attain a considerable size and a long span of life. At least until the 1914 war 

 the Russian government kept fishes of this species that had been marked by Peter the Great 

 in the ponds of Tsarskoe-Selo. When these ponds were being cleaned, the pike were caught and 

 transferred to another pool. This operation was not entirely without danger, for the fish did 

 not hesitate to attack the men in charge of this tricky job. These pike were about 6 feet long. 



Although the perch (Perca fliivialilis) is very voracious it is far from being as dangerous as 

 the pike. It lives on little else but fish. On account of its form it was taken by Guvier as the 



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