BIGELOW: EXPLORATIONS OF THE COAST WATERS. 253 



It is less easy to divide the copepods than other Crustacea into the 

 neritic and oceanic categories because they are pelagic at all stages. 

 Hence, (barring brackish water species) what is neritic in one sea, 

 may prove to be oceanic in another. Nevertheless, since they con- 

 stitute the bulk of the plankton of the Gulf of Maine, I may point 

 out that species which are generally classed as neritic in the North 

 Sea region play only a very subordinate role, if they occur at all, in 

 the central part of the Gulf, our lists containing only five which are 

 so classed by Farran (1910, 1911), Scott (1911), Herdman and Ridell 

 (1911) and Gough (1905, 1907), viz Acartia, Tortanus discaudatus, 

 Centropages hamatus, Eurytemora, and Temora. We have only one 

 or two records for each of the first four outside the outer islands; 

 none from offshore parts of the Gulf (1914a, 1915). The fifth, Temora 

 longicornis, is apparently less closely confined to coastal waters in the 

 western than in the eastern side of the Atlantic for in the summer of 

 1913 (1915) it was generally distributed over the Gulf, though there 

 was no corresponding expansion of other neritic organisms. But as 

 a rule, it is common only locally near land, and over Nantucket Shoals 

 and Georges Bank, a distribution roughlv paralleling that of Cyanea 

 (p. 251). _ 



Finally it is justifiable to refer such fish eggs as are spawned near 

 land, to the neritic category. Examples of this sort, in the Gulf of 

 Maine, are afforded by the Cod and Haddock, which are very rarely 

 encountered outside the 100 meter curve, though spawned all around 

 the periphery of the Gulf within that depth zone (p. 251). 



These facts show, that neritic organisms, strictly speaking, are 

 closely confined to a narrow coastal zone in the Gulf of Maine in 

 summer, and to the shallow banks that form its southern rim; none 

 of them have ever been found in any numbers in the deep central 

 parts of the Gulf; and most of them are unkno'UTi there. This is as 

 good evidence as is salinity (p. 241) that at that season, i. e., after the 

 spring freshets are passed, the land water hugs the coast. In early 

 spring, when the rivers are in flood, conditions may be different; 

 but the water is so cold at that time, that the vernal wave of repro- 

 duction has hardly begun on the part of the littoral fauna. 



The typical, endemic plankton of the center of the Gulf, is composed 

 of species independent of the bottom, ?". e., " haliplankton " ; most of 

 them known to be oceanic as opposed to neritic in European waters. 

 Thus the diatom plankton which^ we encountered offshore in May 

 (p. 324) consisted chiefly of Chacioceras dcnsum and Rhizosolcnia scmi- 

 spina; both so characterized by European students (Gran, 1905; 



