BIGELOW: EXPLORATIONS IN THE GULF OF MAINE. 127 
was it abundant anywhere. A third genus, Beroe, was likewise seen 
often; and all the specimens taken belong to the cosmopolitan species 
B. cucumis, often recorded before from the Gulf. 
RESULTS OF THE QUANTITATIVE HAULS. 
(Plate 7). 
In using the Hensen net for quantitative hauls we were most seri- 
ously handicapped by working from a sailing vessel, because hauls of 
this sort are significant only if the vessel is practically motionless when 
they are taken; and it was impossible to hold the vessel motionless 
with the auxiliary engine in a breeze. Consequently we could carry 
on this line of work only at the stations which were occupied in calm 
weather. Small nets might have been hauled by hand from the dory 
at anchor; but this was not practicable with the large apparatus with 
which we were provided. The qualitative composition of the catches 
made with the Hensen net shows that they did not afford a fair esti- 
mate of the plankton even under favorable circumstances, because 
they seldom yielded any Sagittae; organisms which are plentifully 
represented in the four-foot net hauls. The trouble was, probably, 
that the nets were hauled too slowly, our hoisting engine reeling in 
at a rate of only about ten fathoms (about eighteen meters) per 
minute, which allowed the more active animals to escape. But the 
copepods, which usually form the bulk of the plankton of the Gulf, are 
more fairly represented. These shortcomings make it out of the ques- 
tion to draw any exact conclusion from the hauls. But they serve to 
show, in a general way, the relative richness of the plankton over dif- 
ferent parts of the region. The four-foot net hauls, too, help very 
materially, by supplementing the few quantitative hauls; and although 
I recognize that the various four-foot net hauls are not directly com- 
parable with one another, because rate of towing, etc. is never exactly 
the same at any two stations, and because the level at which the major 
part of the haul was made, with the open nets, might, or might not 
coincide with the zone richest in plankton, yet they do show, in a gen- 
eral way, whether the water was very rich, barren, or intermediate. 
And the fact that the results agree fairly well with those of the Hensen 
nets gives them a greater value than they could be credited with if 
unsupported by this more exact, though less extensive evidence. The 
four-foot hauls were made as nearly comparable as possible, by being 
of the same duration (with few exceptions } hour); and by being made 
