GENERAL INTRODUCTION 17 



the French possess a series of stations along both the 

 Atlantic and Mediterranean coasts of which those at 

 Roscoff and Banyuls respectively are the most important. 

 They have recently founded a station at Salammbo in Tunis. 

 Outside Europe the most important stations are in the 

 United States where the recently extended Laboratory at 

 Woods Hole in Massachusetts (Plate 6) is now by far the 

 largest institution of its kind in the world ; during the 

 summer hundreds of students and research workers visit 

 it but in the winter little is done for there is no permanent 

 scientific staff. Near it is the laboratory of the United 

 States Bureau of Fisheries. Other important stations are 

 situated on the Atlantic and Pacific coasts of Canada and 

 the United States of which perhaps the most interesting is 

 that of the Carnegie Institution on the Tortugas Islands 

 in the Gulf of Mexico. The development of science in 

 Japan has led to the founding of a series of marine stations 

 along their coasts from which valuable work, especially 

 in connection with fisheries and oyster culture, is already 

 being turned out. 



Life in the Sea 



The sea is far richer in different forms of life than the 

 land or fresh water, many groups of animals being exclu- 

 sively marine. Since many of the latter may be quite 

 unknown to readers without special knowledge of biology, 

 it seems advisable, before proceeding with the description 

 of the different zones of life in the sea and the characteristics 

 of their inhabitants, to give in this introductory chapter 

 a short summary of the various groups of marine animals 

 and plants. 



Animals 



Distinguished from all other animals, in that they consist 

 of a single " cell," are the Protozoa. They are extremely 



