208 Fortieth Annual Meeting 



to light with each haul of the net aroused zoologists to the 

 fact that a new world was open to them — a world compris- 

 ing a life of such extent, beauty, and diversity of form and 

 habit that its exploration was undertaken with the greatest 

 enthusiasm ; and the next thirty years, from 1850 to 1880, 

 witnessed marvellous additions to knowledge of the sea 

 fauna, though the classical discoveries of Huxley, Hackel, 

 Kolliker, Leuckart, Gegenbauer, Agassiz, and others. These 

 in turn led to or were concerned with the organization of 

 important governmental exploring expeditions, especially 

 those conducted under the auspices of the United States, 

 Great Britain, Germany, France, and Norway. The most 

 important of these, however, was the epoch-making Chal- 

 lenger expedition of 1873 to 1876, under the direction of 

 Sir Wyville Thompson and Sir John Murray. The results 

 of this voyage were most far-reaching, not only in the great 

 number of new species brought to life, but also in the 

 development of knowledge regarding ocean conditions and 

 the extent to which animal life peoples the sea and its bot- 

 tom. Since 1880, the United States and practically all the 

 European nations have engaged in a continuous series of 

 hydrographic and zoological deep-sea expeditions by means 

 of which knowledge of the ocean and its fauna has rapidly 

 increased up to the present. To enter into details regarding 

 these voyages and their results is beyond the limits of this 

 paper. We may, however, briefly recall certain general 

 features of the life of the sea as it appears in the present 

 state of our knowledge. 



Oceanic life may be considered under three heads — (a) 

 the floating organisms or plankton, (b) the swimming fauna 

 or nekton, and (c) the animals and plants living upon the 

 sea bottom, known collectivel}^ as the benthos. 



(a) The plankton consists of myriads of floating crea- 

 tures, mostly of small size, including especially countless 

 protozoa and unicellular plants, which in swarms of vary- 

 ing density and great extent, seem to people the entire 

 ocean. Agassiz, as a result of his observations during the 

 voyages of the Blake, maintained that this population is 



