BIGELOW: COAST WATER EXPLORATION OF 1913. 267 
THE PLANKTON. 
GENERAL ACCOUNT OF THE MACROPLANKTON. 
The plankton work of the cruise had two main objects: — first, 
a qualitative survey of the various species, which must precede any 
quantitative study to make the latter valuable; and, secondly a 
faunistic examination of the plankton as a whole, at each station, 
to illustrate the geographic occurrence of associations of species. 
When the work in Massachusetts Bay in May, 1913, was finished the 
vernal diatom swarm had largely disappeared, and copepods, which 
had been very scarce during the preceding month, had reappeared in 
the shape of swarms of nauplii and older larvae; while by June, hauls 
off Gloucester yielded an almost pure Calanus plankton. Much this 
same condition obtained early in July, surface hauls off Gloucester, 
on July 7th, yielding a rich harvest of Calanus finmarchicus, with great 
numbers of the large blue copepod Anomalocera pattersoni, together with 
young schizopods, and a few other boreal organisms; while the im- 
portance of this region as a spawning ground for food fish was attested 
by the presence of numerous gadoid fry in the nets. 
The hauls off Cape Cod (Station 10057) revealed the same type of 
macroplankton that occupied the greater part of the Gulf during the 
summer of 1912, namely, swarms of Calanus finmarchicus, a few Eu- 
chaeta norvegica, many small schizopods (Thysanoessa), Euthemisto 
and Hyperoche among amphipods, the pteropod Limacina balea (p. 
| 303); Sagitta elegans (p. 299); the Medusae Staurophora mertensii and 
Melicertum campanula; the. siphonophore Stephanomia cara (p. 315); 
and the ctenophores Beroe cucumis and Pleurobrachia pileus. Al- 
| though open nets alone were used, their contents clearly showed that 
the plankton was bathymetrically stratified. Thus it was the surface 
} hauls alone that yielded any considerable number of copepod nauplii 
| and eggs; and while the haul at 15-0 fathoms caught swarms of 
| Calanus, and many schizopods, and hyperiids, but only a few Sagittae, 
_ the haul from thirty fathoms contained almost no schizopods, hyperi- 
ids, or pteropods, but on the other hand brought back great numbers 
_ of Sagittae; and Euchaeta was taken in the deep haul only; 7. e¢., Ca- 
_lanus, schizopods, hyperiids, and pteropods were mostly above fifteen 
fathoms, Euchaeta, and Sagittae below that depth, Beroe, Pleuro- 
brachia, and Stephanomia more evenly distributed horizontally. 
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