BIGELOW: EXPLORATIONS OF THE COAST ^\ATERS. 283 



Euphausiids, though taken at most of the stations both in 1914 and 

 in 1915, seldom formed an important constitutent of the plankton. 

 However, the haul on Brown's Bank in July, 1914 (Station 1022S, 

 p. 245, Fig. 79) at 60 meters yielded 500 cc. of small individuals of 

 three species of Thysanoessa, T. grcgaria, T. longicaudafa, and T. 

 inermis, with a few Nematoscelis megalops, and large Mcganyctiphancs 

 norvcgica. A few days later we again found a euphausiid plankton, 

 over the continental slope off Shelburne, Nova Scotia (Station 10233, 

 p. 245, Fig. 79) where half hour hauls on the surface, at 100 meters 

 and at 200 meters yielded respectively 125 cc, 500 cc, and 250 cc, 

 with very little else. In this case the surface catch consisted of 

 Euphaiisia krohnii, the catch at 400 meters being Nematoscelis mega- 

 lops, with a mixed swarm of the two at 100 meters. Swarms of eu- 

 phasiid larvae were likewise taken on the surface off Cape Cod in 

 August, of that year (Station 10264) in company with great numbers 

 of large Calanus, while at Stations 10246 and 10254, the nets yielded 

 a swarm of Mcganyctiphancs norvcgica. 



In 1915 we again found Nematoscelis and Euphausia in large num- 

 bers over the slope off Shelburne (Station 10295), though the hauls 

 on BroTVTi's Bank (Station 10296) yielded none at all. The most 

 notable occurrence of euphausiids during that summer was the re- 

 appearance of Mcganyctiphancs norvcgica, associated with the large 

 copepod Euchaeta, in the northeast corner of the Gulf, where it was 

 abundant in the deep haul (125-0 meters) in May (Station 10273); 

 swarmed at about 100 meters in June (Station 10283) and was plenti- 

 ful in the deep water (150-0 meters) in August (Station 10304). 

 But although it was abundant at this same locality both in 1913 and 

 1914, not a single specimen was taken there in 1912 (1914a). At 

 only two other localities in 1915 did euphausiids (Thysanoessa inermis 

 in each case) form a large part of the catch, in the Eastern Basin in 

 May (Station 10270) and off Cape Ann in August (Station 10306). 



Thysanoessa inermis ^ is the commonest euphausiid in the Gulf of 

 Maine, occurring at most of the stations there in 1914 (p. 282), and at 

 twenty stations in 1915 (Stations 10270, 10271, 10273, 10275, 10277, 

 10279^ 10283, 10288, 10290, 10291, 10293, 10304, 10306, 10307, 10309, 

 10310, 10318, 10329, 10332, 10333). But it was lacking in the hauls 

 over the southern edge of Georges Bank, in the Eastern Channel, and 

 at all the stations outside the continental slope, except for a single 

 specimen at 10233. Hansen (1915) ^ records it from off Cape Cod, 



' I follow Hansen (1911) in including both Th. inermis and Th. neglecia under this name. 

 ' Hansen, in this paper, hsts all the earlier captures by the various vessels of the U. S. Bureau 

 of Fisheries in this region. 



