PLANKTON OF THE GULF OF MAINE 67 



centimeters long; 32 the wine-red medusa Periphylla hyacinthina; 13 specimens of 

 its chocolate-colored relative JEginura grimaldii; the iridescent medusae Halicreas 

 papillosum and Rhopalonema funerarium; and many red prawns; side by side with 

 the ehsetognaths Eukrohnia and Sagitta maxima, the large copepod Euchseta norvegica, 

 and the euphausiids Nematoscelis and Thysanoessa, besides boreal animals such as 

 S. elegans, Tomopteris, Limacina balea, and Calanus. 



Scanty though the catch just listed is, compared with the abundant pelagic 

 fauna that has been encountered by the National, the Valdivia, and the Michael Sars 

 at many stations in the North Atlantic, and by the Albatross on many occasions 

 and in localities in widely separated parts of the Pacific, it is the only one in which 

 the black fish-red prawn community has been represented by more than an occasional 

 example even at our outermost stations, though we have towed down to 400 meters 

 or deeper at several other localities off the slope abreast of the Gulf of Maine in 

 February, May, June, July, and August. In fact, to complete our list of captures 

 of this category I have only to add two genera of fishes (Cyclothone and Myctophum) 

 and one red medusa (Atolla) from 750 meters off the southwest face of Georges Bank, 

 February 22, 1920 (station 20044); a few black fish and bathypelagic medusae 

 (JEginura) from 1,000-0 meters southeast of the bank three weeks later (March 12, 

 1920, station 20069); a scattering of bathypelagic fish (mostly juvenile wSternop- 

 tychids and Myctophids) at our summer stations along the same zone off the bank 

 in June and July, and off Cape Sable. 



With bathypelagic animals so scarce in the cool water that washes the continental 

 slope abreast of the Gulf of Maine, and with both the Eastern Channel (the bottle- 

 neck through which, alone, the deeper strata of oceanic water flow into the gulf) 

 and the basin into which it debouches considerably shoaler than the levels at which 

 they attain their maximum development offshore, it would be surprising to find 

 any of them in the inner parts of the gulf except as the rarest of stragglers. As a 

 matter of fact, our cruises have yielded only two such records — viz, one Cyclothone 

 signata 23 millimeters long on Browns Bank, station 10296, June, 1915, and a muti- 

 lated specimen, probably of this same species, taken in an open-net haul from 180 

 meters in the Fundy Deep on March 22, 1920. Nor have other students been more 

 successful in this respect so far as I can learn. Thus it is evident that members 

 of this community occur only accidentally within the limits of the gulf, for did they 

 enter the latter as often even as the tropical animals discussed above, they would 

 have been sure to attract attention in the tow net by their striking appearance. 

 In short, the plankton of the gulf receives practically nothing from the deeper layers 

 of the Atlantic at any season. Even the most temporary invasion on their part 

 would be so important an event, both faunistically and hydrographically, that 

 sharper and more constant watch should be kept for them in the gulf than their 

 rarity there would warrant otherwise. 



The several Tropic and Arctic visitors and immigrants from the continental slope 

 touched on above illustrate the less successful degrees of colonization, ranging from 

 utter failure in the cases of sporadic visits of exotic tropical animals and the equally 



» For a description of this eel see Goode and Bean, 1896, p. 155, fig. 168. It is not included in the report on the fishes o( the 

 Gulf of Maine (Bigelow and Welsh, 1925), because the localities of record lie outside the limits covered therein. 



