626 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
ume of this planktonic mass thus heaped up is often tein or many times 
greater than that in the immediately adjacent parts of the sea. On 
the contrary, the planktonic mass is extraordinarily poor in pelagi¢ ani- 
mals and plants, where by the emptying of great floods a quantity of 
fresh water is brought into the sea and its saltness diminished. Johan- 
nes Miiller pointed out how very much the result of pelagic fishery 
was influenced thereby. Again, on the other hand, the rivers day by 
day bring into the sea a quantity of organic substances which serve as 
food for the benthonice organisms, and since the benthos again stands in 
manifold reciprocal relation to the plankton, since the meroplanktonic 
animals (like the medusie, the pelagic larva of worms, echinoderms, 
etc.) are the means of a considerable interchange between the two, so 
is it easily understood how the distribution of the holoplanktonic ani- 
mals is also influenced thereby and how irregular becomes the com- 
position of the plankton. 
Zovcurrents, or planktonic streams.—Among the most noteworthy and 
important phenomena of marine biology is the great accumulation of 
swimming bodies which form long and narrow bands of thickened 
plankton. <AJl naturalists who have worked at the seashore for a long 
period and have followed the irregular appearance of the pelagic organ- 
isms know these peculiar streams, which the Italian fishermen call by 
the name ‘correnti.” Carl Vogt, in 1848, pointed out their great impor: 
tance for pelagic fishery (17, p. 303). For their scientific designation 
and their distinction from the other marine currents I propose the term 
Zovcurrents or Zodrema.* 
The pelagic aninals and plants are so numerous and so closely packed 
in these zodcurrents as to resemble somewhat the human population in 
the busieststreet of a great commercial city. But millions and millions 
of small creatures from all the above-mentioned groups of planktonic 
organisms are crowded confusedly together, and furnish a spectacle of 
whose charm a conception can be formed only by seeing it. If one 
directly scoops up a portion of this motley crowd with a tumbler, not 
infrequently “the greater part of the contents of the glass (an actual 
living animal broth) is composed of the volume of animals, the smaller 
of the volume of water” (3, p. 171). From a distance these “ crowded 
sea-animal streets” are usually discernible from the smoothness which 
the surface of the sea presents, while close beside it the surface is more 
or lessrippled. Often one can follow such an “ oil-like animal stream,” 
which usually has a breadth of 5 to 10 meters, for more than a kilometer 
without finding any diminution of the thick crowd of animals in it, while 
on both sides of it, right and left, the sea is almost vacant, or shows 
only afew scattered stragglers. At Messina, as at Lanzarote, the phe- 
nomenaof the zodcurrents were especially pronounced. My companion 
*Rema (used in Messina) is from the Greek pevwa = current; comp. 3, p. 172 note. 
