THE PELAGIC FAUNA AND FLORA. 179 
The customary method of collecting these pelagic animals 
from the surface is by means of a tow-net, dragged behind a 
boat as it moves slowly through the water, or hung from the 
sides of the steamer in any weather which allows the handling 
of a trawl or dredge. The contents of the net are emptied 
into glass jars, and carefully examined. The larger speci- 
mens of fishes, of annelids, of crustaceans, of mollusks, and 
of eclenterates, visible to the naked eye, are of course in 
better condition when collected with a hand-net. The smaller 
fry alone survive the 
packing which they 
get at the bottom of 
the tow-net. Fre- 
quent examination of 
the net is important in order to 
obtain in proper condition the 
more delicate pelagic animals. In 
many cases the contents of the 
tow-net consist chiefly of pelagic 
crustacea, among which the pro- 
minent types are the Calani and 
other pelagic copepods. (Fig. 
84.) The many species of Mysis 
(Fig. 85), regular tramps of the 
sea, are with the Calani the great 
marauders of the pelagic fauna, 
attacking at once any of the 
larger animals which show the 
least signs of decay.’ 
pie 
CLILXIDUXTIED HS. 
eer QAU 0 
АГЬ NAWY 2 
гуу. “КМШ 22 
1 Around our coasts and in the Gulf of Mexico and the Caribbean, small Hemi- 
ptera (Halobates) (Fig. 123) are not 
unfrequently met, skimming over the 
surface at a considerable distance from 
the coast. The larva of a species of 
fly (Chironomus) is quite common off 
shore from our northern coasts. The 
“Challenger” found the pelagie Ha- 
lobates very abundant in certain regions — 
of the Pacific. Fig. 123. — Halobates wüllerstorffi. 
8. (Chall.) 
") 
