146 BULLETIN OF THE BUREAU OF FISHERIES 



an immigrant, not as a regular inhabitant, that Th. raschii occurs within the Gulf 

 of Maine, where it occupies much the same faunal niche as the northern copepods, 

 Calamus Jiyperboreus and Metridia longa (pp. 212 and 245). 

 Nematoscelis megalops, G. O. Sars 

 The presence of this euphausiid at our outermost stations has been mentioned 

 in an earlier chapter (p. 56), and we have also found it occasionally within the 

 Gulf— that is, off Mount Desert Rock on August 16, 1912 (station 10032), and 

 at eight stations during July and August, 1914 (Bigelow, 1917, p. 282), as illus- 

 trated on the accompanying chart (fig. 51). Most of these scattering records are 

 from the eastern and southeastern parts of the gulf, as might be expected of a visitor 

 from offshore, and it is probable that the few Nematoscelis that were present over 

 Browns Bank and in the Eastern Channel in July, 1914, represented the innermost 

 fringe of a swarm of this species that populated the waters over the continental 

 slope southeast of Cape Sable at the time. 



Our summer records for Nematoscelis within the gulf are based on very few 

 specimens in each case; nevertheless, this is the season at which it most often 

 occurs, for we have never detected it there or even on Georges Bank during autumn, 

 winter, or spring; but the fact that the Albatross towed it in fair numbers off the 

 western end of Georges Bank on February 22 (station 20044) and southeast from 

 Cape Sable on March 19, 1920 (station 20077), is sufficient evidence that it is to be 

 expected along the continental slope abreast of the gulf during the cold half of the 

 year as well as the warm. It not only occurs more constantly along this belt than 

 within the gulf, but is much more abundant there in actual numbers— witness the 

 large catches made at our outermost stations off Cape Sable by the Grampus on July 

 28, 1914, and June 24, 1915, and off the southern slope of Georges Bank on July 

 24, 1916 (Bigelow, 1922, p. 13S). 



Hansen (1915) likewise records it from many localities over the contmental 

 slope off Marthas Vineyard, but not from the Gulf of Maine, from Georges Bank, 

 or from anywhere on the continental shelf east of Cape Cod. This evidence supports 

 the general thesis (Hansen, 1915; Zimmer, 1909; Kramp, 1913) that Nematoscelis 

 megalops is typically an oceanic form of warm-temperate affinity, at home in the 

 open Atlantic Basin; and since it is known to range as far north as Iceland and to 

 the waters east of Newfoundland during the warm season, it is not surprising that 

 it should occasionally enter the Gulf of Maine with the general indraught into the 

 eastern side of the latter. We have no evidence that Nematoscelis ever breeds there 

 successfully, however, nor is this at all likely, the probable fate of these rare im- 

 migrants being either to withdraw once more to warmer regions as the water cools 

 in autumn (if they have been able to survive the vicissitudes of life in a foreign 

 environment so long), or to perish like other visitors from offshore, such as Thy- 

 sanoessa gregaria and Sagitta serratodentata (pp. 142 and 320). 



Euphausia krohnii, Brandt 



Euphausia Irohnii (the only species representative of this large genus so far 

 detected in the Gulf) has not been taken in the inner parts of the Gulf of Maine 

 but was sparsely represented off the southern slope of Georges Bank (station 10220) 



