BIGELOW: COAST WATER EXPLORATION OF 1913. 337 
that no great change, 2. e., no great ingress of water of either northern 
or Gulf Stream origin had taken place. In both years the plankton 
of the Gulf was typically boreal. But species which we can safely 
say are contributed to the fauna of the Gulf by the surface water of 
the Gulf Stream, 2. e., Salpae, and the warm water siphonophores, 
were distinctly less abundant, and less widespread in the Gulf, in 
1913 than in 1912. On the other hand, several boreal and Arctic- 
boreal species, 2. ¢., Lamacina balea, Calanus hyperboreus, Metridia 
longa, Eucheata norvegica, Eukrohnia hamata, and Aglantha digitale, 
were more prominent faunally in 1913 than in the preceding summer. 
And there is good reason to include Euthemisto bispinosa in the Arc- 
tic-boreal category, judging from its occurrence on the other side of 
the Atlantic and in the Arctic Ocean (Tesch, 1911). This suggests, of 
course, that St. Lawrence water was proportionally greater, Gulf 
Stream water less in amount in the. summer of 1913; the plankton 
thus corroborating the evidence of salinity and temperature (p. 250). 
The general quantitative distribution of the macroplankton was 
much the same for the two years; but the local differences were far 
greater in 1912 than in 1913; and nowhere, in the latter year, was the 
water as barren as the coastal zone east of Penobscot Bay in 1912. 
Whether or not the very rich plankton which was noted in Ipswich Bay 
in 1912, was reproduced there in 1913, is not known, because that exact 
locality was not revisited. 
A question of importance is whether the Gulf as a whole was 
| richer or poorer in macroplankton, 7.e. in food for pelagic fish, in 
1913 than in 1912, and here copepods play the chief rdle. The 
| actual volumes, and relative number of copepods (p. 329) at corre- 
| sponding stations for the two years are given in the table :— 
Station Station Volume Volume Copepods Copepods 
1912 1913 1919 1913 1912 1913 
10002 10087 As 18 239 101 
10025 10089 8 8 125 62 
10028 10092 3 16 25 — 198 
10031 10096 3 12 20 140 
| 10036 10097 3 ? 50 174 
| 10035 10099 Trace 3 10 54 
| ~ 10038 10101 y) 10 24 150 
| 10022 10103 3 7 97 76 
| 10011 10104 2 9 30 54 
Averages 5.5 10.3 69 111 
