PLANKTON OP THE GULP OF MAINE 
149 
reflects the number of tow nettings that have been carried out along that part of the 
slope rather than any general abundance of Meganyctiphanes there, corresponding to 
which we have found it at only one of our stations off the slope of Georges Bank. 
The scarcity of Meganyctiphanes over Georges Bank and in the southeastern 
deeps of the gulf generally, in spring as well as in summer, suggests that the few 
specimens that drift westward beyond Nantucket Shoals along the continental slope 
are migrants, either from along the Nova Scotian coast to the eastward (and possibly 
even from as far away as the Gulf of St. Lawrence) or from the western side of the 
Gulf of Maine, not from the eastern or central parts of the latter. 
The alternation of the seasons sees a corresponding expansion and contraction in 
the area of distribution of Meganyctiphanes in the inner part of the Gulf of Maine. 
Probably this is at its narrowest late in the winter and early in the spring, for from 
February to April, 1920, we had only two records of it anywhere inside the 100-meter 
contour in the whole coastal zone on both sides of the gulf — one for half a dozen 
specimens near Mount Desert Island on March 3 (station 20056), and the other for 
a single specimen off Yarmouth, Nova Scotia, on April 9 (station 20102)— although 
we took it at many stations marked on the chart (fig. 54) in the central and northeast 
deeps of the gulf during that period. Nor did we find it anywhere on Georges or 
Browns Banks during these months. In fact, it is seldom that the local presence or 
absence of any one of the larger members of the zooplankton can be defined so sharply 
as in this instance. Thus it is evident that Meganyctiphanes withdraws altogether 
from the shallows of the gulf within the 100-meter contour during the coldest season, 
unless, perhaps, it persists locally around the shores of the Bay ofFundy; and our 
failure to find it at any of our February-May stations over the continental slope 
abreast of the gulf suggests that it vanishes similarly from this portion of its range in 
late winter and spring. Thus its area of distribution in the Gulf of Maine is then 
cut off from its more northerly centers of occurrence by an extensive zone off southern 
Nova Scotia and extending around Cape Sable, where there are no Meganyctiphanes 
at that season, which is not the case for Thysanoessa inermis (p. 135) or for Th, 
longicaudata (p. 139). 
During the later spring and early summer Meganyctiphanes disperses in all 
directions in the Gulf of Maine, to occupy the much more extensive range over which 
we have found it occurring in midsummer, and reappears over the slope off Marthas 
Vineyard. 
The contraction of the range of Meganyctiphanes, from its maximum in summer 
and early autumn to the spring state just outlined, may commence as early as October 
in the western side of the gulf, for we have not taken it anywhere in the Massachusetts 
Bay region in October, November, December, or during the winter of 1912-1913. 
It persists until later in the coastal belt north of Cape Ann, where we towed it near 
the Isles of Shoals and off Monhegan Island on November 1 and 2, 1916 (stations 
10400 and 10402) ; off Cape Elizabeth, near Mount Desert Island, in the northeastern 
part of the basin, in the Fundy Deep, and off Lurcher Shoal during the last days of 
December and first week of January of the winter of 1920-1921 (stations 10494, 
10497, 10499, 10500, and 10502). 
