PLANKTON OF THE GULF OF MAINE 295 



In the last instance there were 7 per cent of this species in a very scanty catch of 

 copepods made with the open net towing horizontally at 150-0 meters. 



It will be noted that the dates of these offshore captures do not correspond 

 with the seasonal periodicity of the species at St. Andrews, but with a species aa 

 rare as this is out at sea it is largely a matter of luck whether any given haul chances 

 to pick it up, and if the catch of other copepods be large, it is equally a matter of luck 

 whether the particular sample of the tow examined chances to contain it. 



Tortanus discaudahis is thus so strictly neritic in the gulf (decidedly more so than 

 in the Gulf of St. Lawrence, where it is widespread over the shoal southern part) that 

 it is hardly a factor at all in the offshore plankton, but probably it enters regularly 

 into the diet of the small herring and other young fishes among the islands and in the 

 harbors of the gulf, judging from its abundance at St. Andrews. 



Undeucheeta major Giesbreclit 



This species is probably worldwide in temperate and tropic latitudes in the 

 oceanic basins. It has been recorded off the west coast of Ireland in the north 

 and from several stations below the Equator down to 40° S., 35° E., off South Africa 

 in the south. It was originally described from the central Pacific and has since been 

 taken off southern California (Giesbrecht, 1895) and at San Diego (Esterly, 1905) 

 in that ocean. U. major has not yet been found in the Mediterranean but has been 

 reported from the Indian Ocean (van Breemen, 1908) and among the Malay Archi- 

 pelago (A. Scott, 1909). 



Previous records for this species off the Atlantic coast of North America are 

 one station outside the continental edge off New Jersey, in July, 1913 (Bigelow, 1915, 

 p. 287, station 10071), and three Canadian fisheries stations in July, 1915 — one out- 

 side the continental edge off La Have Bank, one at the same relative location somewhat 

 farther east off Banquereau Bank, and the third in the oceanic basin off the mouth 

 of the Laurentian channel between Sable Island Bank and the Newfoundland Banks 

 (Willey, 1919). To these Dr. C. B. Wilson's table (p. 299) adds two vertical hauls 

 in the Gulf of Maine — one of them on Browns Bank (March 13, 1920, station 20072) 

 and the other on German Bank (April 15 of that year, station 20103). In each 

 instance there were about 10 specimens in the catch, being at the rate of about 50 

 per square meter. 



In the Gulf of Maine this copepod is one of the rarest of strays from the oceanic 

 basin offshore, locally interesting when it occurs as an indicator of the prevailing 

 indraught. Not having been taken farther in than German Bank, it may be assumed 

 to be shorter-lived in the gulf than the species of Eucheirella, Pleuromamma. or 

 Rhincalanus, which are similarly exotic and immigrant in the gulf. 



Undeucliseta minor Giesbrecht 



The distribution of this species parallels that of U. major and it is equally 

 oceanic. In the North Atlantic it has been reported as far north as the Faroe- 

 Shetland channel (lat. 61° 20' N.) and west of Ireland; as far south as latitude 35° 

 (Wolfenden, 1911; With, 1915); it is known from the central Pacific and from off 



