BIGELOW: EXPLORATIpXS OF THE COAST WATERS. 301 



cina, appears to occupy a role intermediate between Limacina halca 

 and L. hclicina in the Gulf, occurring irregularly, usuallx- in small 

 numbers. But though it never attains the fauna! prominence there 

 that it does further north, and has been decidedly rare in recent years 

 (1914a, 1915), it is recorded by Wood as swarming in Portland Harbor 

 in May, 1868, when "the water appeared to be alive with them" 

 (Wood, 18G9, p. 185). However, such occurrences are certainly 

 exceptional, as is its occasional appearance, in numbers, as far west 

 as New York (De Kay, 1843, p. 6). Whether they are due to invasions 

 by northern Mater, or to local propagation, is an open question. 



The summer records (1914a; 1915) show that Clione may be ex- 

 pected anywhere in the Gulf; and it is no more regular in its occur- 

 rence in the eastern than in the western side, contrary to what might 

 be expected of a cold-water organism, and to what is actually the case 

 with Limacina hclicina (p. 300). But it was distinctly seasonal in 

 1915, for while it was taken at most of the stations in May, (Stations 

 10266, 10269, 10270, 10271, 10272, 10276, 10277, 10278, 10279, 

 10280), it occurred at only about half the June stations (Stations 

 10281, 10282, 10284, 10286, 10287, 10288, 10293, 10294), and while 

 we have occasional records for July and August (1914a, 1915), it was 

 not taken in September or October, 1915; nor off Massachusetts Bay 

 November or December, 1912 (1914b, p. 404), though it reappeared 

 there in small numbers in January and February, 1913. Our records 

 added to Wood's account, point to spring as its season of greatest, 

 abundance in the Gulf. 



Clione is one of the most prominent members of the macroplankton 

 of the Arctic Ocean (Meisenheimer, 1905b; Damas and Koefoed, 

 1907, Paulsen, 1910) ; and it swarms in the polar waters of the Labra- 

 dor Current off the east coasts of Newfoundland and Labrador, where 

 I myself found it in great numbers among the floe ice, in the summer 

 of 1900. The apparent correspondence between its seasonal maxi- 

 mum, and the seasonal fluctuations of the Cabot Current in the Gulf ^ 

 of Maine, suggests that its numbers there are recruited from the north. 

 But its distribution within the Gulf does not correspond to the north- 

 ern water there, as does that of Limacina hclicina (p. 300), Mertensia 

 (p. 248), or the Arctic Oikopleura. On the contrary, Clione was as 

 numerous in the western as in the eastern part of the Gulf (p. 248) 

 even in May. It was rare in the Cabot Current oft' southern Nova 

 Scotia in summer (Stations 10233, 10235, 10243, a total of four speci- 

 mens in 1914: Station 10294, one specimen in 1915). 



In reality, as Damas and Kofoed point out (1907, p. 361), Clione 

 limacina is not the sure index to Arctic water that many have supposed, 



