584 KKPOKT OF COMMISSIONER OF FISH AND FISHERIES. 

 IV.— SUMMARY OF THE PLANKTONIC ORGANISMS. 



A. — PliorOI'llYTI'.S Ol' TIIK I'l.AXKTON. 



Tlie iniicelJiiUtr plantn (Protophi/ta*) have vory great importance 

 in the i)hysiology of the plankton and tlie cycle of matter in the 

 sea {Sioffwechsel dcs Meeres), for they furnish by far the greater j)art 

 of the fundamental food {Vniahrviu/). The inconceivable amount of 

 food Mhich the countless myriads of swimming marine animals consume 

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

 and in this the unicellular protophytes are of much greater importance 

 than the multicellular metaj^hytes. Nevertheless the natnral history 

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

 no botanist has attempted 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 gTou])S, uot 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 opinion hitherto been much under- 

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

 lies 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. Many of these, indeed, have been regarded as protozoa or- as 

 eggs of i>lanktonic metazoa. 



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

 fication of the protophytes, we must keep in the foreground the follow- 

 ing considerations: (1) Tlie kind of reproduction, whether by simple 

 division {Schito^Jhyta) into two, four, or many parts, or by formation 

 of motile swarm-spores, Mastigoplif/fa; (2) the constitution of the phy- 

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

 protoplasm of the cell (usually in the form of graimles), and has great 

 significance in assimilation (chlorophyll, diatomin, erethrin, pha^odin, 

 etc.); (3) the nunphological and chemical constitution of the (•ell-mem- 

 brane (cellulose, siliceous, capsular, or bivalvular, etc.). So long as Ave 

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

 fundamental process of vegetal assimilati(m, for the synthesis of proto- 

 l)lasm and iimylum, 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 



*Tho8oparation of the Prolophyta fromtlio Metaphyia is as .iuetifiable as that of the 

 Protozoa from tho Mefazoa. The hitter form tissues, the former do not. (Compare 

 Naturl. Sihr>pfui)gso;eschi(hli-, viii Aiill., 1SS9, ]>]). 120-453.) 



