622 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
(3) the nerocurrents (the littoral currents or local coast currents); and 
(4) the zodcurrents (the local planktonic streams or very crowded animal 
roads). 
Halicurrents or ocean streams.—The unequal distribution of plank- 
ton in the ocean -is in great part the direct result of the oceanic 
currents. In general the proposition is recognized as true that the 
great ocean streams, which we briefly designate as halicurrents, effect 
a greater accumulation of Swimming organisms and thereby are 
richer in plankton than the halistasa or “still streams,” the extensive 
regions which are inclosed by them and relatively free from currents. 
For a long time the richness in plankton which characterizes the Gulf 
Stream on the east coast of North America, the Faikland Stream on 
the east coast of South America, and the Guinea Stream on the west 
coast of Central Africa, has been known. Less understood and investi- 
gated than these Atlantic streams, but also very rich in varied plankton, 
are the great streams of the Indian and Pacific oceans, the Monsoon 
Stream on the south coast of Asia, the Mozambique Stream on the east 
coast of South Africa, the Black Stream of Japan, the Peru Stream on 
the west coast of South America, ete. 
It is very difficult, from the numerous scattered accounts of the 
pelagic fauna and flora of these great ocean currents, to form a general 
picture of them, but it is now possible to draw from them the conelu- 
sion that generally the plankton of the halicurrents, qualitatively as 
well as quantitatively, is richer than the plankton of the halistasa, or 
the great oceanic sea basins around which flow the great streams and 
counter streams, and which meet the first glance on every recent map 
of the marine currents. * 
In defending this proposition I rely especially upon the rich experi- 
ence of the two most important plankton expeditions, of the Challenger 
(6) and of the Vettor Pisani (8), and also upon my own comparative 
study of several hundred plankton samples, which were collected in 
part by Murray, in part by Capt. Rabbe, in the most diverse parts of 
three greatoceans. The planktonic wealth of the great halicurrents is 
most remarkable at the place where they are narrowest, when the 
masses of swimming animals and plants are most closely pressed 
together. Highly remarkable here is the opposition which the rich 
pelagic fauna and flora of the stream forms in qualitative and quanti- 
tative relation to the sparse population of the immediately adjacent 
halistase. As the temperature and often even the color of the sea 
siDhe Semaine Piplonieal enon en Be ime igen seems te me a form one 
of the nearest and most pressing problems of planktology, and also of oceanography. 
Apart from the smaller and little investigated Arctic and Antarctic regions, in all 
five great areas of quiet water ought to be distinguished, namely: (1) the North 
Atlantic halislase (with the Sargasso Sea); (2) the South Atlantic (between Benguela 
and Brazil streams); (3) the Indian (between Madagascar and Australia); (4) the 
North Pacific (between California and China), and (5) the South Pacitic halistase 
(between Chili and Tahiti). 
