374 BULLETIN OP THE BUREAU OF FISHERIES 



basin and the shoaler coastwise zone, except that we have not found it over the coastal 

 banks along western Nova Scotia — that is, German Bank and near Lurcher Shoal. 

 It is probable, however, that we have simply missed it there. The concentration 

 of records in the Massachusetts Bay region, if anything more than accidental, sug- 

 gests that this is the chief center of abundance for Beroe in the Gulf of Maine. 15 



Our experience has been that it is a rare event for Beroe to appear in large 

 numbers anywhere in the open gulf; in fact, our tow nets have seldom yielded more 

 than 15 or 20 at any station — a population quite insignificant as compared with the 

 swarms of Pleurobrachia so often encountered — -while a large percentage of our 

 records of Beroe have been based on one or two specimens each or on broken frag- 

 ments. Our failure to find a single Beroe on Georges Bank, either during the cold 

 season (February to May, 1920) or the warm (July, 1914 and 1916) is difficult to 

 account for when it occurs so nearly universally in the basin a few miles to the 

 north, is not rare on Browns Bank to the east, and has been taken repeatedly along 

 the continental shelf farther west and south. Certainly the shoal water over the 

 bank can not be responsible for its apparent absence there, for Beroe is common at 

 still shallower localities inshore — for instance, at Provincetown Harbor and in 

 Massachusetts Bay — nor is there anything in temperature or salinity to suggest 

 that the physical state of the water on the bank is locally unsuitable for it. Nor 

 is our failure to find it over German Bank on any of our several visits to that locality 

 less puzzling, for the local swarm of Pleurobrachia would serve Beroe as food instead 

 of preying upon the latter, as they do on the sundry crustacean members of the 

 plankton. 



According to L. Agassiz (1S60) the earliest specimens of Beroe appear in Massa- 

 chusetts Bay early in July, when they are only 1 to 1J^ inches long, to grow there 

 to three or four times that size by August. Corresponding to this time-table, 

 Alexander Agassiz (1874) found them spawning from July or early August to early 

 September, and took the young stages, from egg to fully formed Beroe, during that 

 same season. Not all of the adults are destroyed by the September storms, as L. 

 Agassiz supposed, for a tow in the western basin on November 1, 1916 (station 

 10401, SO-0 meters) yielded many fragments of Beroe with turgid sexual organs, 

 and the 75-0 meter tow off Gloucester, December 29, 1920 (station 10489), brought 

 back parts of one which must have been 40 to 50 millimeters high when alive — that 

 is, it was large enough to be mature. Thus it is evident that Beroe breeds more or 

 less regularly until well into December off Massachusetts Bay (probably in other 

 parts of the gulf as well), and it is certain that a few mature and breed there during 

 the later winter, for we have taken very young specimens less than 10 millimeters 

 long at several stations in various parts of the gulf in March, April, and May. 16 

 The fact that most of the Beroe that have been taken in the gulf between November 



" For locality records (or 1913 and 1914 see Bigelow, 1915, p. 316. and 1917. p. 303. It was also taken (or seen floating) at stations 

 10002, 10000, 10007, 10009, 10011, 10012b, 10019, 10023. 10036, 10040, 10043, and 10047 in 1912; at stations 20044, 20050, 20052, 20053, 20055, 

 20056,' 20067, 2006S, 20071, 20079, 200S1, 200S6, 20087,200S8, 20097, 20105, 20112, 20114, 20115, 20118, 20119, 20126, and 20129 in the spring 

 of 1920; and at stations 10488, 10489. 10491, and 10194 during December, 1920, and January, 1921. 



'• Center of gulf, Mar. 3, station 20053; off Mount Desert Rock, Mar. 3, station 20055; between Mount Desert Rock and Mount 

 Desert Island, Mar. 3, station 20056; southeast slope of Georges Bank, Mar. 12, station 20067; Browns Bank, Mar. 13, station 

 20072; Fundy Deep, Mar. 22, station 20079; northern channel between Browns Bank and Cape Sable, Apr. 15. station 20105; 

 southeast of Cape Cod, May 17, station 20126; and on the southwest slope of Georges Bank, May 17, station 20129; all in 1920. 



