264 BULLETIN OF THE BUREAU OF FISHERIES 



Oitliona siniilis Claus 



This species has variously been described as "world-wide" (Farran, 1910) and as 

 Arctic, with southern extension (Willey, 1920). The first would seem to fit it best, 

 for it has been taken from Barents Sea, Spitzbergen, and from the Arctic coasts of 

 Alaska and Canada (Willey, 1920) in the north, right down the whole extent of the 

 North and South Atlantic to latitude 35° S., and beyond that to latitude 60 to 

 65° S. in the Antartic south of Kerguelen Island. It is likewise widespread in the 

 Red Sea and in the Indian Ocean and about Ceylon; it is also reported from the 

 Pacific and New Zealand, occurs in the Mediterranean, has been taken at the Cana- 

 ries, is plentiful about the British Isles, enters the Baltic, and is abundant along the 

 whole coast of Norway, in the Norwegian sea, and in Barents Sea." It occurred in 

 practically every one of Herdman's gatherings right across the North Atlantic and 

 through the Gulf of St. Lawrence from Liverpool to Quebec (Herdman, Thompson, 

 and Scott, 1898). T. Scott (1905) also lists it from the Gulf of St. Lawrence, but the 

 only other published records for it on the eastern coast of North America are for 

 Woods Hole (Wheeler, 1901; Fish, 1925) and Rhode Island (Williams, 1907). 



This species appears in Doctor McMurrich's plankton lists for St. Andrews during 

 December and January in about two-thirds of the hauls; less frequently during 

 February and March (about 50 per cent of the hauls). During the late spring, 

 summer, and early autumn until mid-October, it was found in about 11 per cent of the 

 hauls. This indicates a winter plurimum for the species, but at no season was it as 

 abundant as the larger calanoids, being almost always recorded in the lowest of the 

 four classes of abundance (1 to 4) used by Doctor McMurrich. 



Oithona similis was not found in any of the earlier towings in the open gulf, but 

 being so frequent at St. Andrews and so widely distributed over the high seas else- 

 where, probably this slender little copepod has usually slipped through the com- 

 paratively large-meshed nets used for the vertical hauls and for the horizontals for 

 which the copepods have been listed. This seems the more likely because the 

 Canadian fisheries expedition did not take it at all in many hauls in the Gulf of St. 

 Lawrence, where Herdman found it in almost every gathering. This is corroborated 

 by Doctor Wilson's report of it at several stations in 1920 and 1921, as noted below 

 in his supplementary note on the copepods (p. 306). 



Perhaps no marine planktonic copepod exists over a wider range of temperature 

 and of salinity than does this little cyclopid. Equally at home in the tropic Indian 

 Ocean, in polar seas close to the freezing point, in the brackish Baltic (it has been 

 found there in salinity as low as 7 per mille), and in the very salty surface water of the 

 Gulf of Suez and Red Sea (salinity upwards of 38 per mille), it is not likely that 

 either of these factors determines its seasonal periodicity or regional distribution in 

 the Gulf of Maine. 



Paracalanus parvus (Claus) 



This species is probably cosmopohtan in temperate and tropical seas, the localities 

 from which it has already been reported being almost "world wide" (Farran, 1910, 

 p. 61) except for the Arctic and Antarctic. These include the northeastern Atlantic 



" For further details see Giesbrecht (1892); Sars (1918); Farran (1910); Thompson and Scott (1903); Wolfenden (1911); Willey 

 (1920); van Breeman (1S08). 



