BIGELOW: EXPLORATIONS IN THE GULF OF MAINE. 107 



Norway, the English Channel, the northeast coast of Scotland, and 

 from the Grand Banks of Newfoundland; and Sagitta elegans is a 

 characteristic member of the North Sea plankton. 



Most oceanic species so far detected in the collections, e. g., Salpa 

 mucronata, and 8. fimformis, Sagitta scrratodcntata, Agalma elegans, 

 Physophora Iii/drostatica, are dwellers in warm or in temperate waters, 

 the only far northern records of any of them being obviously the 

 result of warm currents (for northern records of Salpa, see Apstein, 

 1909: of Sagitta scrratodentata, see Ritter Zahony, 1911; Agalma and 

 Physophora, see Bigelow, 191 1 . And the resemblance which the Gulf 

 bears in a small way, to the Norwegian Sea in the more important 

 constituents of its zoiiplankton, is heightened by the fact that Salpa, 

 Agalma, and Physophora are regular summer visitors to the latter 

 with the northward movement of Atlantic water (Helland Hansen 

 and Nansen, 1909, Murray and Hjort, 1912), while their presence in 

 our Gulf is positive evidence of an influx of water from the northern 

 edge of the Gulf Stream. 



List of fishes. 

 (Identified by W. W. Welsh, U. S. Bureau of Fisheries). 

 1. Larval and postlarval stages taken in the plankton hauls. 



Argentinidae. 



Smelt. Osmerus mordax (Mitchill). 

 Portland Harbor July 31 Surface 1 specimen 19.5 mm. 



Herring Smelt. Argentina silus Ascanius. 

 Station 27 August 14 35 fathoms 1 specimen 49 mm. 



Gasterosteidae. 

 Three-spined Stickleback. Gasterosteus aculeatus Linne. 



