340 BULLETIN OF THE BUREAU OF FISHERIES 



among the most reliable of indicators of ocean currents. Huntsman (1921, p. 89) 

 has remarked that failure to find it more frequently along Nova Scotia "indicates 

 the smallness of the contribution given by the water covering the Newfoundland 

 Bank to the mass of water passing southwestward over the Breton and Scotian 

 Banks." In fact, the evidence so far at hand suggests that it is exceptional for 

 Tomopteris of Newfoundland Bank origin to stray southwestward much beyond 60° 

 longitude, much more so for it to reach the Gulf of Maine by this route. 



What r61e T. catharina plays in the economy of the planktonic community is still 

 to be learned. 



Tomopteris septentrionalis Apstein 



Tomopteris catharina is the only species of the genus which so far has been recog- 

 nized anywhere in the inner parts of the Gulf of Maine at any season, but during March, 

 1920, a second and much smaller tailless Tomopteris, provisionally identified as T. 

 septentrionalis, il was taken over the outer edge of the continental shelf off Cape 

 Sable (stations 20076 and 20077), on Brown's Bank (station 20072), and in the south- 

 eastern part of the Gulf basin (station 200S6) ; also in the Eastern Channel (station 

 20107) in April and off the southwest slope of Georges Bank in May (station 20129), 

 one or two specimens on each occasion (fig. 94) . 



These records are interesting as extending the known range of this species 

 southward along America to the Gulf of Maine. It was found off Halifax and at the 

 mouth of the Laurentian Channel by the Canadian fisheries expedition of 1915 

 (Huntsman, 1921); has been taken at many localities in the Labrador current from 

 the Grand Banks northward; along the west coast of Greenland; right across the 

 North Atlantic to the Hebrides (Apstein, 1900); off Ireland, where Southern (1911) 

 described it as common; and as far south as the region of the Canaries and as the 

 Mediterranean near Gibraltar (Malaquin and Carin, 1911). It is likewise recorded 

 from the South Pacific off Chile (Rosa, 1908). 



Unlike T. catharina, T. septentrionalis, is characteristically oceanic, but its 

 status in regard to temperature is not yet understood. 



PELAGIC CCELENTERATES 



The Gulf of Maine supports many species of coelenterates, which live pelagic 

 for at least part of their lives. Most of them, however (medusa stages of hydroids) , 

 are strictly neritic animals, which find their most favorable environment in the 

 sheltered bays and among the islands and on the offshore banks, and which so seldom 

 stray more than a few miles away during the brief period during which they are 

 afloat that they are of practically no importance in the plankton of the gulf basin. 

 Animals belonging to this category need not concern us here, since they have seldom 

 if ever dominated in our offshore catches. Most of the local species have been de- 

 scribed and beautifully illustrated by Alexander Agassiz (1865), to whom I refer 



8i The distinguishing characters of this species are its lack of tall, of rosette organs, or of first cirri; the development of sex organs 

 only In the dorsal branches of the parapodia; and the presence of one glandular organ in each ventral branch of the latter. There 

 is no danger of confusing septentrionalis,with the much larger catharina, specimens of the former, sufficiently adult to bear 21 

 parapods, being only 12 millimeters long, according to Reibisch (1905). Our largest with 17 parapods was 7.5 millimeters. The 

 separation from T. planktonis, which depends on the parapodial glands, requires specimens in good condition. 



