36 BULLETIN OP THE BUREAU OF FISHERIES 



The pelagic eggs of the many species of fish that spawn on the banks or in shallow 

 water alongshore in the gulf are as rarely found in our tow nettings outside the 100 or 150 

 meter contours as are other neritic organisms. Cod, haddock, and several species of 

 flatfish may serve as examples of this; likewise the silver hake (Bigelow and Welsh, 

 1925, p. 488, fig. 217, and p. 244); while the eggs of the cunner are closely confined 

 to the coast line and to the vicinity of the outer islands and shoals (Bigelow and 

 Welsh, 1925, p. 284). 



The locality records for the neritic animals just summarized, and for sundry 

 others belonging to the same category, are concentrated in a rather narrow coastal 

 zone paralleling the periphery of the gulf and over its shallow southern rim, with 

 neritic forms very seldom of any importance in the planktonic community more than 

 a few miles out at sea in summer, except for the shallow offshore banks. The fact 

 that most of the animals of this category, if not wanting in the central basin of the 

 gulf, are at least so scarce there as to have been overlooked, is sufficient evidence 

 that the plankton of the coastwise belt has little tendency to disperse seaward at 

 that season, but that the eddylike circulation parallels the coast, which is corroborated 

 by drift bottles and by oceanographic evidence generally. 



With few exceptions the scarcity of pelagic animals of neritic origin in the offshore 

 parts of the gulf leaves the planktonic communities that people its open waters (not 

 only in the central basin but right up to the outer headlands) composed of animals 

 and plants not only independent of the bottom at all times but most of which are 

 equally oceanic as opposed to neritic in European waters, as appears from the very 

 extensive records accumulated by the International Committee for the Exploration 

 of the Sea. However, they are not the product of the Atlantic basin outside the 

 continental slope, as the term "oceanic" might imply, but of the banks water that 

 washes the continental shelf on both sides of the Atlantic, and to which they are 

 confined off the North American littoral by the high temperatures of the tropical 

 water farther offshore. 



The diatom plankton encountered over the basin in May, 1915, typified by Cliseto- 

 eeras densum and Khizosolenia semispina, belongs to this category (p. 434; Gran, 1915; 

 Ostenfeld, 1913; Herdman and Riddell, 1911), while the Ceratium community, 

 which usually occupies the Gulf of Maine as a whole throughout the summer (p. 391), is 

 also characterized by species (Ceratium tripos and C. longipes var. atlantica) usually 

 regarded as oceanic in the North Sea region (Paulsen, 1908; Jorgensen, 1911) 

 and in the Norwegian Sea (Gran, 1902). This is equally true of most of the pelagic 

 animals most constantly characteristic of the plankton of the gulf; for example, of the 

 copepods Calanus finmarchiens, Pseudocalanus, Euchseta, and Metridia (Damas, 

 1905; Gran, 1902; Farran, 1910; Herdman and Riddell, 1911); of the amphipods 

 Euthemisto bispinosa and E. compressa (Tesch, 1911; Sars, 1895); of the pteropod 

 Limacina retroversa (Paulsen, 1910); and of the euphausiid shrimp Thysanoessa 

 inermis (Tattersall, 1911; Kramp, 1913a), to mention only a few of the most typical. 

 While two of the most important of its members, f aunistically (Sagitta elegans and Mega- 

 nyctiphanes norvegica), are intermediate between oceanic and neritic in their biologic 

 status in the North Sea region (Apstein, 1911; Kramp, 1913a), in the Gulf of Maine 

 they cover practically the same range as the more typically oceanic forms just men- 

 tioned. Off the European coast most of these species— in fact, the Calanus commu- 



