158 BULLETIN OF THE BUREAU OF FISHEBIES 



by a large tropical element (e. g., station 10218, July 21, 1914). Thus its abundance 

 along the outer edge of the shelf does not imply an oceanic origin, but, hke Calanus, 

 it is typical of the water of the coastal banks off the Gulf of Maine and along the 

 American litoral as a whole, finding the inner edge of the so-called Gulf Stream a 

 fluctuating barrier to its seaward dispersal, which is in line with its boreal nature. 



Euthemisto is not only more numerous over the outer part of the shelf than 

 within the Gulf of Maine, but it grows larger there, although very large specimens 

 occasionally occur even close to land. When adult females with eggs are taken in 

 our coastwise hauls they are seldom over 10 millimeters long, with the general run 

 of the catch still smaller, whereas the numerous adults taken over the offshore banks 

 are often as long as 20 millimeters. 



Although we know little of the status of Euthemisto in the offshore parts of 

 the gulf in autumn, there can be little doubt that an inshore movement of greater 

 or less extent takes place at that time, for in 1915 this genus occurred in some numbers 

 in October in Massachusetts Bay, where it is usually scarce or absent in summer 

 (p. 156). Apparently it reaches its maximum abundance in the coastal zone of the 

 gulf in October and November, and during the third week of November in 1912 it 

 was comparatively common near Gloucester (Bigelow, 1914a, p. 403). To judge 

 from the season of 1920 and 1921, however, this autumnal increase is followed by 

 shrinkage in its numbers with the onset of winter, for in late December and early 

 January we took Euthemisto at only 5 out of 14 stations in the northern and western 

 parts of the gulf — never more than a few specimens in any haul — nor did it appear 

 in any abundance later than November during the winter of 1912-1913, though a 

 few were noted at all our stations until February. 



In February and March, 1920 (fig. 56), Euthemisto was as generally distributed 

 over the gidf and over Georges and Browns Banks, as it is in summer (fig. 55) ; but it was 

 far less numerous, for it appeared at only about half the February and March stations 

 (occasional examples only) , the only exception to this rule being the waters off south- 

 ern Nova Scotia (not strictly within our limits) , where it was taken in some numbers 

 on two occasions (stations 20074 and 20075). Its numbers in the gulf fell to an even 

 lower ebb in April, when we detected it (in very small numbers) at only 6 out of 30 

 stations, a shrinkage due to an actual decrease in the stock and not to an emmigra- 

 tion out of the gulf, for, as it happens, these few records were near Cape Elizabeth, 

 on the one hand, and off the western shores of Nova Scotia, on the other, with no 

 Euthemisto whatever taken at our stations farther out at sea during the month. 



In 1920 none were detected in the western side of the gulf in May (stations 

 20120 to 20126), though a few (both bispinosa and compressa) were taken off the 

 seaward slope of Georges Bank on the 17th (station 20129), in a haul from 100-0 

 meters; but in 1915 (which was also an earlier season in other respects) a scattering of 

 Euthemisto was noted at most of the May and June stations at the mouth of Mas- 

 sachusetts Bay, in the gulf generally outside the 100-meter contour, off Lurcher 

 Shoal, on German and Browns Banks, and over the outer part of the continental 

 shelf outside the continental edge off Shelburne, Nova Scotia. 86 During these months 



"« Recorded in my field notes from stations 10269, 10270, 10272, 10273, 10278, 10279, 10281, 10282, 10284, 10288, 10290, 10291, 10293, 

 10294, 10295, and 10296. 



