226 BULLETIN OF THE BUREAU OF FISHERIES 



The salinities of the open waters of the Gulf of Maine lie so far inside the limits 

 within which C. typieus has been found abundantly in other seas that this is probably 

 not an important factor in its local distribution horizontally or vertically. Cer- 

 tainly no part of the gulf can ever be too salt for an animal occurring regularly in 

 salinities of upwards of 35 per mille in European seas. Toward the other extreme, 

 C. typieus is common in salinities of 31 to 32 per mille at Woods Hole, and one of 

 our largest catches was in water of about 31.5 per mille (on the surface off New York, 

 July 12, 1913, station 10066); but the fact that this species is apparently absent 

 from the Baltic makes it probable that it is more susceptible to low salinity than its 

 relative, C. hamatus, which is generally distributed there, and thus suggests that 

 the very lowest salinities of the surface along shore in the gulf (below 30 per mille) 

 at the time of the spring freshets may be unfavorable for it. 



Dactylopusia thisboides (Claus) 



The known distribution of this harpacticoid 2< includes Franz Josef Land, Bear 

 Island (south of Spitzbergen) , the north and west coasts of Norway, the British and 

 French coasts, Mediterranean, Red Sea, and Woods Hole, Mass., where Sharpe 

 (1911) collected it among algae on sandy bottom in about 2 fathoms of water in 

 July, the latter being the only previous American record. It is also reported from 

 Kerguelen in the southern Indian Ocean, from the collections of the German South 

 Polar Expedition (Brady, 1910), but until these southern specimens are described 

 it remains doubtful whether they are actually identical with the northern form. 

 Brady (1878-1880) dredged this species in all kinds of situations, from brackish 

 water, on the one hand, out to depths of 40 fathoms, on the other, among weeds on 

 bottom; but it has been found only close to land and is not usually planktonic. 



At St. Andrews, where the stirring of the water by violent tides is probably 

 responsible for bringing it up to the top, Doctor McMurrich lists a few specimens 

 on one occasion only — a tow at 7 fathoms on April 5. This record is interesting 

 as extending its known range to the littoral zone of the Gulf of Maine, but it is hardly 

 to be expected in the plankton of the open sea there. 



Dwightia 26 gracilis (Dana) 



This species is widespread in the warmer parts of all three great oceans. In the 

 Atlantic it has been taken at various localities from latitude 36° 44' S. to latitude 

 52° 27' N. (west of Ireland) in the east, and northward to the Gulf of Maine in the west, 

 most frequently in the tropical zone between latitudes 10° S. and 30° N. It also 

 occurs far and wide in the Mediterranean (Thompson and Scott, 1903). In the 

 Red Sea, Arabian Sea, Indian Ocean down to the latitude of the Cape of Good 

 Hope, and among the Malay Archipelago it has been reported from so large a pro- 

 portion of tow nettings that it can be described as universal (Thompson and Scott, 

 1903; Cleve, 1901, 1903; and A. Scott, 1902, 1909); and the German South Polar 

 Expedition had it at Kerguelen and even farther south (Brady, 1910; Wolfenden, 1911). 



" This has been summarized, with quotation of authorities, by Sars (1903-1911) and Sharpe (1911). 



» C. B. Wilson (1924), finding that the generic name Setella, by which this species has long been known, was preoccupied by 

 Schrank in 1902 for a genus of Lepidoptera, has proposed Dwightia in its place. 



