608 REPORT OF COMMISSIONER OF FISH AND FISHERIES, 
in succession as great areas as possible” (23, p. 525). In a more 
remarkable way he adds: “‘Thereby has resulted the furnishing of a 
fixed basis for a thorough quantitative and qualitative analysis of 
marine organisms.” According to my view such ‘fixed basis” was 
obtained long ago, particularly by the widely extended investigations 
of the Challenger expedition (from January, 1873, to May, 1876), fitted 
out with all appliances. This embraced a period of forty months, and 
included ‘the whole expanse of the ocean.” ‘Their experience ought 
to lay claim to much greater value than that of the National, whose 
voyage of three months took in only a part of the Atlantic, and was in 
addition trammeled by bad weather, accidents to the ship, early loss of 
the large vertical nets, and other misfortunes in the carrying out of their 
plans. It is hardly conceivable how an “exact investigator,” from so 
incomplete and fragmentary experience, can derive the “fixed basis” 
for new and far-reaching views, which stand in remarkable contradic- 
tion to all previous experience. 
It would here lead too far, if, from the numerous old and new narra- 
tives of voyages, I should collect the observations of seafarers upon 
the remarkable inequality of the sea population, the different fauna and 
flora of the regions of currents, the alternation of immense swimming 
swarms of animals and almost uninhabited areas of sea. It is sufficient 
to point out the two works in which the most extensive and thorough 
knowledge up to this time is collected, the “‘ Narrative of the Cruise of 
H. M.S. Challenger,” edited by John Murray (6), and the “ Collezioni 
della R. Corvetta Vettor Pisand” (8), published by Chierchia. Since the 
general chorological and cecological results in these two principal works 
agree fully with my own views gained from thirty years’ experience, I 
pass immediately to.a general exposition of these latter, reserving their 
proof for a later special work. 
A.—POLYMIXIC AND MONOTONIC PLANKTON, 
The constitution of the plankton of swimming plants and animals of 
different classes is exceedingly manifold. In this regard I distinguish 
first two principal forms, polymixic and monotonic plankton.* 
The “mixed tow-stuff (Awftrieb), or the polymixie plankton,” is com- 
posed of organisms of different species and classes in such a way that 
no one form or group of forms composes more than the one-half of the 
whole volume. The “simple tow-stuff, on the other hand, or the monotonic 
plankton,” shows a very homogeneous composition, while a single group 
of organisms, a Single species or a single genus, or even a single family 
or order, forms very predominantly the chief mass of the capture, at 
least the greater part of the entire volume of the plankton, often two- 
thirds or three-fourths of it, sometimes even more. Under this mon- 
otonic plankton one may again distinguish prevalent plankton, when 
the predominant group forms up to three-fourths of the total volume, 
* TloAbucktog = much oe eae MavoTovog = Sol a ae form, ae 
