582 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
covered by Chierchia, which were taken by him in great numbers and — 
in great vertical and horizontal extension, but never higher than 1,000 
meters below the surface and never deeper than 1,000 meters above 
the sea bottom (8, p. 85). The deepest part of this zonary fauna forms 
the bathybie plankton (or the profound tow-stuff, Auftrieb), i. ¢., animals 
of the deep sea, which only hover over the bottom but never touch it, 
whether they stand in definite relation to the abyssal benthos or not. 
One might also call them “abyssal plankton,” if it were not more prac- 
-ticable to limit the term “abyssal” to the (vagrant and sessile) benthos 
of the deep sea. To the bathybie plankton belong many phodaria, 
some medusze and siphonophores, many deep-sea crustacea, Tomopteris 
euchwta, Megalocereus abyssorum, ete. (15, pp. 55-57). 
In each of these vertical parts of the plankton, distinctions may be 
made which apply to the horizontal distribution. We may also dis- 
tinguish oceanic and neritic forms in the pelagic fauna as in the zonary 
and bathybie fauna. 
AUTOPELAGIC, BATHYPELAGIC, AND SPANIPELAGIC PLANKTON. 
If, following the old custom, we limit the term ‘pelagic bios” to those 
organisms which, at some time, swim or float at the surface of the sea— 
if we do not with Chun (15, p. 45) extend this term to the zonary and 
bathybic animals—it still is necessary to further distinguish by differ- 
ent terms those forms of life which constantly, temporarily, or only 
exceptionally live at the surface of the sea. I suggest for these the 
terms autopelagic, bathypelagic, and spanipelagic. Autopelagic are 
those animals and plants which are constantly found only at the sur- 
face (or in stormy weather at slight depths below it), the “superficial” 
of Chun (15, pp. 45, 60). To this “‘constant superficial fauna” belong, 
for example, many polycyttaria (most spheerozoids), many meduse (e. g., 
Hucopide), and many siphonophores (e. g., Forskalide); further, the 
lobate ctenophores (Hucharis, Bolina), particular species of Sagitta (e. g., 
bipunctata), and many copepods (e. g., Pontellina, 15, p. 27). 
I call bathypelagic all those organisms which occur not merely at the 
surface, but also extend down into the depths, and often fill the deep 
layers of the ocean in not Jess astonishing multitudes than the surface 
layers. Chun designates such bathypelagic animals as “interzonary 
pelagic animals” (15, p. 45). Here belongs properly the chief mass of 
the plankton; for through the agreeing researches of Murray (5, 6), 
Moseley (7), Chierchia (8), and Chun (15, 16), as well as from my own 
wide experience, it becomes highly probable that the great number of 
pelagic animals and plants only pass a part of their lives at the surface; 
swimming at different depths during the other part. Among the 
bathypelagic animals there are farther to-be distinguished: (a) Nycti- 
pelagic, which arise to the surface only at night, living in the depths 
during the day; very many medusie, siphonophores, pyrosoma, most 
