180 SEA FISHERIES 



habits and traditions of its ancestors. It lives as best 

 it can, incessantly tossed about between life easy and 

 spacious, life strenuous and difficult, and inevitable 

 death. It is precisely between these two limits that it 

 asserts its momentary independence of its environment. 

 The expression is unfortunate, I know, and betrays our 

 ignorance of the incredible complexity of biological 

 determinism ; but it also expresses the incontestable 

 truth that the independence of the fish in respect of 

 this element or that of its present environment results 

 from its dependence on its own history. 



IV 



The profound and definite individuality of the fish is 

 manifested in many ways. 



There is a general law which impels all living crea- 

 tures to tend to leave their own domain. Not all succeed, 

 but all try. The zostera, those marine plants which form 

 the coastwise sea-meadows, grew of old in the open air. 

 The sardines of the Breton straits frequently leap out of 

 water. M. Racovitza once observed, in Rosas Bay, a 

 shoal of anchovies which was attacked by a bank of 

 mackerel. The unfortunate fish were collected in a com- 

 pact mass, in the midst of which there was no longer any 

 water. The mass of living, struggling creatures assumed 

 the form of a cylinder ; it was animated by three kinds of 

 movements : a movement of translation, a gyratory move- 

 ment, and an up and down movement ; and the upper 

 portions sought to escape into the atmosphere. The 

 grey mullet are a leaping species. Turning on their 

 sides in the water, and bending their bodies in an arc, 

 they leap up and along to a great distance. Eels in 

 making their way back to the sea often leave the rivers 

 and wriggle through the grass. Certain exotic fish, like 



