PLANKTON OF THE GULF OF MAINE 
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Eurytemora herdmani. 
Gaidius tenuispinis. 
Halithalestris croni. 
*Harpacticus litoralis. 
*Harpacticus uniremis. 
Heterorhabdus spinifrons. 
*Idya furcata. 
Labidocera sestiva. 
Lucicutia grandis. 
Metis ignea. 
Mecynocera clausi. 
Metridia longa. 
Metridia lucens. 
Monstrilla serricornis. 
Oithona similis. 
*Parathalestris jacksoni. 
Phyllopus bidentatus. 
Pleuromamma (genus). 
Pseudocalanus elongatus, 
Rhincalanus cornutus. 
Rhincalanus nasutus. 
Scolecithricella minor. 
Temora longicornis. 
Tortanus discaudatus. 
Undeuchaeta major. 
Undeuchaeta minor. 
*Zaus abbreviatus. 
*Zaus spinatus. 
Acartia clausi Giestoreclit 
This species has a more southerly distribution than A. longiremis, ranging widely 
on both sides of the temperate North Atlantic, southward from western Norway on 
the one side and from the St. Lawrence River on the other; but it was not found in 
any of the samples of Arctic plankton examined by Sars (1900) and at only one station 
north of the Arctic Circle in the collection of the Canadian Arctic expedition (Willey, 
1920) . In general, it may he described as neritic, as opposed to oceanic, for although 
it is widely distributed in the oceanic areas of the North Atlantic, European students 
have found it most plentiful in coastal waters such as the Irish and English Channels 
and the southern parts of the North Sea. It is found plentifully in water as little 
saline as 18.42 per mille, but salinities much lower than this apparently bar it (Farran, 
1910). Willey (1920) has characterized it as more of an estuarine form than A. 
longiremis, but the distribution outlined below for the Gulf of Maine shows that this 
can hardly be laid down as a general rule. Steuer (1923) has recently charted its 
distribution in the Eastern Atlantic and generally. 
In a continuous collection of plankton from Liverpool to Quebec, made by Sir 
Wm. Herdman in 1897, it disappeared at longitude 38° 6' W. and did not reappear 
until the ship was well up the St. Lawrence River (Herdman, Thompson, and Scott, 
1898). T. Scott (1905) reports it from the Gulf of St. Lawrence, but Willey (1919) 
did not find it among the many samples which he reported on thence, and if not 
wholly wanting it is at least so rare over the continental shelf off Nova Scotia and 
south of Newfoundland that the Canadian fisheries expedition took it at only one 
station — this, curiously enough, the outermost on the line off Cape Sable (Willey, 
1919). 
It was not detected among the collections made by the Grampus between Cape 
Cod and Chesapeake Bay in 1913 or in 1916, though its relative A. tonsa swarmed 
locally off Delaware Bay during August of the latter year (Bigelow, 1922, p. 146). 
Neither did Wheeler (1901) nor Sharpe (1911) find it at Woods Hole, where A. tonsa 
is one of the commonest of copepods. It is not uncommon there during some winters, 
for Fish (1925, fig. 46) found it regularly from October, 1922, to February, 1923, 
It does not appear in Fowler’s (1912) list of Rhode Island copepods, but Williams 
(1906 and 1907) describes it as abundant in Narragansett Bay in January and 
