BIGELOW: COAST WATER EXPLORATION OF 1913. 339 



than in oceanic water (Farran, 1910). And though Temora longicornis 

 and Euchaeta norvegica are rather more northern, neither of them is 

 distinctively polar. The only members of the copepod fauna which 

 can be classed in that category, Calanus hyperboreus, and Metridia 

 longa, are rare in the Gulf. The two oceanic copepods which are promi- 

 nent in the Gulf belong, one, Anomalocera patter soni, to the temperate 

 Atlantic, the other, Metridia lucens, to rather more northern waters 

 (Cleve, 1900) ; Pleuromamma and Euchirella alone are clearly of Gulf 

 Stream origin, so far as the Gulf of Maine is concerned. 



Only six species of euphausiid schizopods have yet been detected 

 in the plankton of the Gulf (1914b, p. 410). One of these, Meganycti- 

 phanes norvegica, is very widely distributed in the North Atlantic, 

 but much more abundant in boreal water than in polar or warm waters; 

 two, Thysanoessa incrnis, and raschii are tjpical Arctic-boreal forms, 

 one, Thysanoessa longicaudata, is rather more northern, but not polar, 

 being found as far south as the southern part of the North Sea, and 

 one, Neviatoscelis megalops is oceanic, of very wide distribution in the 

 North Atlantic. (For the general distribution of these species, see 

 Kramp, 1913b). To one species only, Thysanoessa gregaria can a 

 southern or Gulf Stream origin be assigned (Zimmer, 1909, p. 21), 

 and this one has seldom been taken in the Gulf. 



The only hyperiid amphipods which attain any faunal importance 

 in the Gulf, Euthemisto compressa and E. bispinosa, are typical Arctic- 

 boreal species, neither of them being found south of the English 

 Channel in European waters. Of the two, bispinosa is decidedly the 

 more northern (Tesch, 1911) which is suggestive in connection with 

 the incursion of this species into the Gulf during the autumn of 1912 

 (p. 335). 



The only pteropod which is common in the Gulf, Limacina balea, 

 is one of the most typical of boreal organisms, at home neither in pure 

 polar water, nor in the warmer parts of the Atlantic (Meisenheimer, 

 1906, Paulsen, 1910). Clione limacina is rather more northern, espe- 

 cially abundant on the Grand Banks of Newfoundland, though not 

 an index of polar water (Murray and Hjort, 1912, p. 108). 



The only chaetognath which is uniformly abundant over the Gulf 

 as a whole, Sagitta elegans, has its centre of distribution in boreal 

 coastal waters, though its extreme range includes the Mediterranean 

 on the one hand, and the Arctic Ocean on the other (Apstein, 1911; 

 Ritter-Zahony, 1911). The two other species which were taken in the 

 Gulf in 1913 are of diametrically opposite origins: — Sagitta serrato- 

 dentata is a southern species; Eukrohnia hamnta is Arctic or from 



