322 BULLETIN OF THE BUREAU OF FISHERIES 



off Mount Desert Island, and in the eastern basin, as well as on the outer edge of 

 the continental shelf and over the slope off Shelburne, Nova Scotia (stations 10281, 

 10282, 10286, 10294, 10295, and 10296). By the 1st of August it may be expected any- 

 where over the southern and eastern parts of Georges Bank, in the eastern channel, 

 on Browns Bank, in the eastern side of the gulf generally, and as far westward along 

 the coast as outlined on the accompanying chart 72 (fig. 89). As the summer ad- 

 vances S. serratodentata continues to spread westward, until by August we have 

 found it very generally distributed over all parts of the gulf where we have towed 

 during that month, right across from Massachusetts to the Nova Scotian Bank, 

 though still with a decided preponderance of locality records for the eastern side 

 (p. 58), reminiscent of the fact that it enters the gulf chiefly between the eastern 

 part of Georges Bank and Cape Sable, perhaps not in the western side at all. The 

 Canadian fisheries expedition likewise found it plentiful on the banks off southern 

 Nova Scotia late in July; also at most of the stations along and outside the con- 

 tinental edge and in the trough of the Laurentian Channel, marking a considerable 

 expansion in its range in this general region since May, but not at all on the banks 

 off Cape Breton or on the Newfoundland Banks. 



Judging from captures in 1915, it continues as widespread in the gulf during 

 September and probably throughout October, also, when we found it at localities as 

 widely separated as off Machias, Me., off Mount Desert Island, Massachusetts Bay 

 (two stations), and the continental edge off Marthas Vineyard. 



S. serratodentata reaches its maximum expansion and greatest abundance in the 

 gulf during the late summer and early autumn, the precise date no doubt varying 

 from year to year. Later in the autumn it disappears. In some years it seems 

 that this happens as early as the first week in November, for we did not find it at 

 any of the stations in the western side of the gulf from October 31 to November 8 

 in 1916 (stations 10399 to 10404); but in 1912 there were a few in Massachusetts Bay 

 on November 20 (station 10047; Bigelow 1914a, p. 403). Although S. serratodentata 

 was not detected anywhere in the inner part of the gulf during the December to 

 January, 1920-1921, cruise of the Halcyon, the fact that odd specimens were towed 

 off Gloucester on December 14, 1912 (station 10048), and January 16, 1913 (station 

 10050), and none on December 23 (station 10049) suggests that a scattering may 

 continue to exist in Massachusetts Bay for a month or two after they have vanished 

 from other parts of the gulf. 



No attempt has been made to estimate the numerical strength of S. serrato- 

 dentata in the gulf, but, as I have previously remarked (Bigelow, 1917, p. 297), 

 we have always found it subordinate to S. elegans early in the season — that is, until 

 August — and in the western part of the gulf at all seasons. In fact, most of the 

 Gulf of Maine records from west of Penobscot Bay and north of the continental 

 edge have been for odd individuals or at most for a few dozens per haul; but during 

 August and September we have found it predominant over S. elegans at the several 

 stations in the eastern side of the gulf marked on the chart (fig. 89), and once swarm- 

 ing (station 10032, August 16, 1912). In July and August, 1914, "Sagitta serrato- 



" For station records for 1912 to 1915, on which this statement is based, see Bigelow, 1914, p. 121; 1914a, p. 403; 1915, p. 297; and 

 1917, p. 294. 



