264 
BULLETIN OF THE BUREAU OF FISHERIES 
OitHona similis Claus 
This species has variously been described as “ world-wide” (Farr an, 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. 42 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. 
Paracalauus parvus (Claus) 
This species is probably cosmopolitan 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 
42 For further details see Giesbrecht (1892); Sars (1918); Farran (1910); Thompson and Scott (1903); Wolfenden (1911); Willey 
1920); van Breeman (1908). 
