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BULLETIN OF THE BUREAU OF FISHERIES 
reappear there in October and later. This seasonal cycle is just the reverse of what 
obtains in the North Sea region, where Euthemisto compressa occurs commonly in 
winter with the indraught of Atlantic water (Tesch. 1911), but only in small numbers 
at other seasons. 
The presence of adults with eggs, of larvae, and of immature specimens at various 
stages in development shows that Euthemisto 87 breeds successfully over the entire 
area of the Gulf of Maine outside the outer islands and headlands — perhaps even in 
Massachusetts Bay. Large numbers of young are sometimes produced in the inner 
parts of the gulf — for instance, the swarms of young off Penobscot Bay in August, 
1913, mentioned above (p. 20) — as well as in the surface waters of the western basin, 
where newly hatched as well as medium-sized Euthemisto were plentiful on August 
31, 1915 (station 10307). The chief breeding areas, as indicated by relative abun- 
dance, lie over the outer edge of the continental shelf, extending as far west at least 
as longitude 71°, where we found shoals of young specimens as well as of adults late 
in August in 1913 (Bigelow, 1915, p. 281) ; likewise on the central, northwestern, and 
southwestern parts of Georges Bank, on Browns Bank, and in the coastal waters 
off Cape Sable. In this general zone we have not only found breeding adults as 
well as young on many occasions, but more than once have taken young in abundance 
on the surface and adults with eggs in the deeper hauls (p. 163). 
The breeding season of Euthemisto certainly extends over a large part of the 
year, for we have found its larvse in every month from February until October. 
Probably it also breeds during the late autumn, when we have not visited its chief 
offshore areas of reproduction, for occasional young specimens appeared in our 
tows near the Isles of Shoals and off Cape Cod in the first week in November, 1916 
(stations 10400 and 10403), and in the deep near Cape Ann late in December, 1920 
(station 10389) ; but young are produced in greatest number in June, July, and 
August. 
No attempt has yet been made to estimate the actual numerical strength of 
Euthemisto in the Gulf of Maine, but at times the local population must be con- 
siderable to yield the abundant tow-net catches mentioned above (p. 156). 
In the preceding lines the genus has been treated as a unit. The relative 
fluctuations of its two local representatives, the species compressa and bispinosa , 88 
are next to be considered. Although these two species of Euthemisto are often 
taken side by side, they occupy somewhat different faunal niches, with bispinosa 
the more oceanic of the two and showing a more definite seasonal movement toward 
and away from the coast than compressa does. 89 During the period February to 
May, when the genus as a whole is at a low ebb in the Gulf, compressa is decidedly 
the commoner member of the pair in its inner waters, while on Georges Bank and 
south of Nova Scotia the two occur in roughly equal numbers at that season (at 
least such was the case in 1920). In June, when the numbers of the genus as a 
whole increase, compressa still predominates within the gulf, but we found bispinosa 
87 Both B. compressa and E. bispinosa. 
88 For descriptions and the distinguishing features of these two see Sars, 1895. I have elsewhere given tables of the relative 
abundance of the two for several of our cruises (Bigelow, 1914a, p. 4; 1915, p. 279; 1917, p. 287; 1922, pp. 133 and 148). 
88 For tables of the relative abundance of the two species of Euthemisto from 1913 to 1915 see Bigelow, 1915, p. 282, and Bigelow 
1917, pp. 287 and 288. 
