PLANKTON OF THE WOODS HOLE REGION U3} 
same month. Just as a northerly movement takes place in summer a southerly 
one is noticeable in late fall and winter. More complete data will be necessary to 
verify these statements, but it is evident that this species is most likely to be taken 
at Woods Hole from late fall until early spring. 
The young of Thysanoéssa longicaudata in the late “ cyrtopia”’ stage were com- 
paratively abundant from May 10 to June 24, 1899. From this data it would 
seem that the adults enter the shallow waters during the breeding season of May 
and June. Bigelow found them abundant only in the center of the Gulf of Maine 
during the fall. This species, according to Zimmer, is also a cold-water form. 
It oceurs occasionally in Vineyard Sound and quite frequently out beyond the 
Gulf Stream. As the young have never been taken since 1899, it is probable that 
the occurrence is not annual, but was due to unnatural conditions. Figure 53 
gives the seasonal distribution for that year. 
One specimen of Huphausia krohnit was taken on June 22, 1899, and another 
on November 9, 1922. Off the Atlantic coast they were taken in abundance in 
July and August. This is asouthern species and 
may be expected to enter Vineyard Sound in the 
summer months. A single specimen of EH. tenera Se 
appeared on October 30, 1923. 
A battered specimen of the genus Thysano- 
poda was taken’on June 23, 1922. The condi- 
tion of the carapace made a determination of the 
species impossible. This was unfortunate be- 
cause, although three species are recorded from the 
western Atlantic, each has been taken on only one 
occasion. Thysanopoda xqualis (H. J. Hansen) 
was recorded nearest the Woods Hole region. N.. 
; A single specimen of Meganyctiphanes BO Se Hee ea ene eR cae ts Th jtonneece 
vegrea, taken April 25, 1906, was found in the  tongicaudata in surface collections of 1898 and 
surface collections of Mr. Edwards. This is a 18%: (One adult on December 12, 1898) 
very common boreal Atlantic species, and it is surprising that more have not been 
taken in Great Harbor. 
The following Schizopoda were taken in surface collections at Woods Hole: 
Thysanoéssa inermis (Kroyer), T. longicaudata Kroyer, Euphausia krohnit Brandt, 
Meganyctiphanes norvegica (Sars), Thysanopoda sp., and Euphausia tenera Hansen. 
Seven species of stomatopod larve have been recorded from the Woods Hole 
region, although but two species of adults occur here. Most of the larve are 
East Indian forms carried north by the Gulf Stream. The various members of the 
order are known to have an extremely long pelagic life with many larval stages. 
This, no doubt, accounts for the tropical larve occasionally appearing in Great 
Harbor. The larval Squillide are of two forms—the Alima and the Erichthus 
form. All the species recorded locally, with the exception of Chloridella, belong 
to the latter form. 
Adult Chloridella empusa (Say) are rather scarce in the immediate vicinity of 
Woods Hole, and for that reason the larve are not abundant in the plankton. 
8242°—25}—_5 
