PLANKTON OF THE GULF OF MAINE 
19 
surface waters were alive “with young amphipods (Euthemisto) as well as with young 
stages of Oalanus jinmarchicus, in the proportion of about one of the former to 
four of the latter” (fig. 15), off Penobscot Bay and off Mount Desert Island on 
August 11, 1913 (Bigelow, 1915, p. 274, stations 10091 and 10092); that older Euthe- 
misto (fig. 16) were plentiful (though not rivaling the copepods) off Cape Ann and in 
the western basin on August 31, 1915 -(stations 10306 and 10307), and at several sta- 
tions along the outer edge of the offshore banks (p. 156) ; that the pteropod Limacina 
retroversa (fig. 17), which, as a rule, is but sparsely represented in our tow nettings, 
swarmed off Penobscot Bay on August 11 and 14, 1913 (stations 10091 and 10101); 
that fragments of a siphonophore (Stephanomia) formed fully half the catch of the 
40-meter haul off Cape Cod on July 8 of that same year (station 10058) ; and that the 
ctenophore Pleurobrachia pileus often fills the water to the exclusion of almost every- 
thing else in the neighborhood of German Bank (fig. 18). 
In summer and early autumn the large medusae Cyanea, Aurelia, and Stauro- 
phora often gather in vast numbers in narrow lanes or windrows, though usually for 
brief periods (p. 362), and at this same season the hydroid medusa Phialidium lan- 
guidum is often so abundant on the surface that it fills the tow net to the brim 
(p. 350). Young fish, too, sometimes occur in numbers sufficient to loom large in the 
total catch, notable instances of which have been the swarming of young silver hake 
off Cape Cod, mentioned above (p. 18) ; likewise of young rosefish (Sebastes) near 
Cape Elizabeth on July 19, 1912 (station 10019), when several hundreds were taken 
(Bigelow, 1914, p. 101), off Massachusetts Bay on August 9, 1913 (station 10087), 
and near Cashes Ledge, September 1, 1915 (station 10308). Occasionally we have 
encountered notable quantities of fish eggs, particularly of squirrel hake ( Urophycis 
chuss), in Ipswich Bay, July 16, 1912 (station 10008); of silver hake (Merluccius) 
near Monhegan Island and off Mount Desert, on August 4 and 18, 1915 (stations 
10303 and 10305); of cunners (Tautogolabrus) at many localities along shore in sum- 
mer, especially in Massachusetts Bay 7 (station 10340-10343); and of haddock over 
their spawning grounds on Georges Bank during the early spring (fig. 19). 
In summer, generally speaking, copepods are relatively most abundant in the 
western side of the gulf, less so in the eastern, the result being that, in spite of the 
qualitative uniformity of the tow nettings from station to station, their general 
aspect is usually most monotonous off the coasts of Massachusetts and. southern 
Maine and out thence to the western basin, and most diversified in the central parts 
of the gulf and in its deep eastern trough. The only notable exception to the mid- 
summer dominance of calanoids anywhere in the open gulf north of its offshore 
banks (local swarmings of other animals, such as those just mentioned, seldom rival 
the copepods in actual abundance, whether measured by bulk or by numbers) is the 
Pleurobrachia swarm of the German Bank region, which I have already described 
in the several preliminary reports on our cruises (Bigelow, 1914, 1915, and 1917). 
Since we have found this ctenophore in abundance at that same general locality dur- 
ing the successive Augusts of 1912, 1913, and 1914, and again on September 2, 1915, 
this is evidently a regular phenomenon of summer. Having occasion to recur to it in 
a later chapter (p. 365), I need add here only that Pleurobrachia, large and small, 
*The ledges off Cohasset are a very productive nursery for this fish, judging from the quantities of its eggs that are to be found 
there 
