584 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

 IV.— SUMMARY OF THE PLANKTONIC ORGANISMS. 



A. — riionjPllYTKS OK TIIK PLANKTON. 



The vniceUnJiir plants {Protopliyta*) have very great importance 

 ill the physiology of the phinktoii and the cycle of matter in the 

 sea {^ioffweclisel des Meercs), for they furnish by far the greater part 

 of the fundamental food {Uniahrung). The inconceivable amount of 

 food which the countless myriads of swimming marine animals consume 

 daily is chiefly derived, directly or indirectly, from the planlctonic flora, 

 and in this the unicellular protophytes are of much greater importance 

 than the multicellular metaphytes. Nevertheless the natural history 

 of these small plants has thus far been very much neglected. As yet 

 no botanist has attemi)ted to consider the planktonic flora in general, 

 and its relation to the planktonic fauna. Only that single class, so rich 

 in forms, the diatoms, has been thoroughly investigated and .systemat- 

 ically worked up; as regards the other groui>s, not a single attempt at 

 systemization has been made; and many simple forms of great impor- 

 tance have lately been recognized for the first time as unicellular plants. 

 I must, therefore, limit myself here to a brief enumeration of the most 

 important groups of the plankton flora. Its general extent and quanti- 

 tative development have in my opiniou hitherto been much under- 

 valued, and with reference to the cycle of matter in the sea {Staff wecJtsel 

 (les Meeres) deserve a thorough consideration. I find masses of various 

 protophytes everywhere in the plankton, and suspect that they have 

 been neglected chiefly because of their small size and inconspicuous 

 form. ]\rany of these, indeed, have been regarded as protozoa or as 

 eggs of planktonic metazoa. 



As a foundation for a most important province of botany, the classi- 

 fication of the protoi)hytes, we must kee]) in the foreground the follow- 

 ing considerations: (1) The kind of reproducticm, whether by simple 

 division {Schizophyta) into two, four, or many parts, or by formation 

 of motile swarm-spores, Ma.stigopln/fa: (2) the constitution of the i)hy- 

 tochroms, of yellow, red, or brown pigment, which is distributed in the 

 protoidasm of the cell (usually in the form of granules), and has great 

 significance in assimilation (chlorophyll, diatomin, erethrin, i>h;eodin, 

 etc.); (3) the morphological and chemical constitution of the cell-mem- 

 hrane (cellulose, siliceous, capsular, or bivalvular, etc.). So long as we 

 hold to the present view of the vegetable physiologists, that for the 

 fundamental process of vegetal assimilation, for the synthesis of proto- 

 plasm and amylum, the presence of the vegetal pigment matter is nec- 

 essary, we can regard as true protophytes only such unicellular organ- 

 isms as are provided with such a phytochrom, but we will have to 



* The separation of tlie Protopliyta from the Metaphyta is as justifiable as that of the 

 Protozoa from the Metazoa. The latter form tissues, the former do not. (Compare 

 Natiirl. Sc'ho])fungsgesohichte, viii Aufl., 1889, jtp. 420-453.) 



