120 BULLETIN OF THE BUREAU OP FISHERIES 



tember, though in other years it has appeared in numbers off Casco Bay in summer, 

 as just noted (p. 119). Apparently it partially withdraws from the Bay of Fundy 

 in autumn, for McMurrich found only occasional examples at St. Andrews from the 

 first week of October until the new year. 



It is not yet possible to plot the distribution of Limacina over the gulf as a 

 whole for winter, our December- January cruise having been confined to the 

 northern and western parts; but there, at least, Limacina is as widespread during 

 early winter as it is in summer; and if the season of 1920-1921 be representative, 

 it is even more regularly distributed, for it occurred at 10 out of 14 tow-net stations, 

 both in Massachusetts and Ipswich Bays near land, and from Cape Cod to Nova 

 Scotia offshore (stations 104S8 to 10491, 10493, 10495, 10496, 10497, and 10500 to 

 10502). Similarly, Stimpson (1854) described it as present in Massachusetts Bay 

 from February until April, more than half a century ago, though the fact that it 

 appeared in the tow near Gloucester late in November, 1912, and again in Feb- 

 ruary, 1913, but neither in December nor in January of that winter, shows that it is 

 as subject to sporadic fluctuations in abundance there during the cold season as dur- 

 ing the warm. 



Failure to find Limacina in the Fundy Deep on January 4, 1921, with McMur- 

 rich's record of it as only occasional at St. Andrews during the half-year from Decem- 

 ber to May, 61 suggests that it occurs less regularly and is much less plentiful in the 

 Bay of Fundy in winter than in summer, which is just the reverse of its seasonal 

 history in Massachusetts Bay. 



If the season of 1920 can be taken as representative, Limacina withdraws from 

 the whole northern and eastern part of the gulf and likewise from the immediate 

 coastal zone in the western side during the last few weeks of winter or first days of 

 spring, for we did not take a single specimen anywhere in the guff during that 

 March or April north or west of the undulating curve laid down on the accompany- 

 ing chart (fig. 44) ; although Limacina in various stages in growth then occurred 

 irregularly along Cape Cod, in the western, southern, and southeastern parts of 

 the basin, and over and off the slope of Georges Bank. 



Our records point to the months of March and April as the season when the 

 geographical range of Limacina in the Gulf of Maine is least extensive, and to the 

 area just outlined as the only part of the gulf where this pteropod is regularly present 

 the year round. With the advance of spring it once more spreads over the northern 

 corner of the gulf, occurring at four stations in the eastern side of the basin in May, 

 1915; but while a considerable augmentation in its numbers takes place in the St. 

 Andrews region (which probably mirrors conditions in the Bay of Fundy generally) 

 by late June, as reflected by the frequency of captures listed by Doctor McMurrich, 

 this does not happen in the coastal zone of the gulf west and south of Mount Desert 

 until three months later, as just noted. 



In this connection it is interesting that Limacina is present all the year round 

 off the west and south coasts of Ireland, just as it is in the offshore waters of the 

 Gulf of Maine, but is seasonal along the Irish shores, with its maximum in spring 



•> From his plankton lists for 1915 and 1916. 



