THE PROGRESSION OF LIFE IN 

 THE SEA. 



ADDRESS TO SECTION D (zOOLOGY) BY 



E. J. ALLEN, D.Sc, F.E.S., 



PRESIDENT OF THE SECTION. 



The method we usually follow in the ordinary course of zoological work 

 is to make first, with the unaided eye, a general examination of the 

 animal that interests us, and then study in detail its separate parts 

 with a simple lens, with a low power of the microscope, with gradually 

 increasing powers, until, finally, minute portions are examined with the 

 highest oil-imimersion lens. The successful research worker is generally 

 one who, whilst carrying to the utmost limit he can achieve his search 

 into detail, maintains as by instinct a true sense of proportion and 

 holds firmly to the idea of the organism as a whole. 



In discussing the living organisms of the sea I shall try to follow 

 a similar plan, thinking of the life of the sea as a whole, built up of 

 individual plants and animals, each in intimate relation with its sur- 

 roundings, and all interdependent among themselves. But even this 

 is not enough, for we must take still a wider view and keep in mind 

 not only the life of the waters, but that also of the land and of the air, 

 for both, as we shall see, have a bearing on our theme. Deep oceans, 

 coastal waters, shallow seas, rivers and lakes, continents and islands, 

 all play their part in one scheme of organic life — life which had, it seems, 

 one origin, and notwithstanding migrations and transmigrations from 

 water to land, from land to air, and from land and air back again to 

 the water, remains one closely inter-related whole. 



Both Brandt* and Gran^ have recently emphasised the fact that it 

 is in the coastal waters and shallow seas, which receive much drainage 

 from the land, that plant and animal life are most abundant, the more 

 open oceans far from land being relatively barren ; as Schiitt puts it, the 

 pure blue of the oceans is the desert colour of the seas. This increased 

 production in the coastal waters is due principally to the presence of 

 nitrogen compounds and compounds of phosphorus derived from terres- 

 trial life. From forest, moor and fen, wherever water trickles, the life 

 of the land sends its infinitesimal quota of these essential foodstuffs to 

 fertilise the sea. 



When, however, we go back to the beginning of things, we shall 

 probably be right if we say that any influence of terrestrial life upon 

 life in the sea must be left out of account. Different views are still 



' Wisscn.fch. Mccrcvuntcnf. Kiel, 18. 1916-20. p. 187. 

 ' Hull. Planktoniquc. Cons. Internat., 1912 (1915). 

 1922 U 



