152 
BULLETIlSr OF THE BUREAU OF FISHERIES 
CUMACEA 
The Cmnacea occupy a place in the plankton shnilar to that of the amphipods. 
Large numbers are often taken at the surface during the breeding season, the 
females carrying eggs or larvae. This particular group differs from the Arthrostraca 
in the length of the breeding season. Females of two species {Diastylis sculpta 
and Cydaspis variens) were found carrying eggs at various times between July and 
January, although both species were most abundant in September and October. 
Females of Oxyurostylis smithi were also found with eggs on October 19. With 
the exception of the greater nimiber taken diu-ing the breeding season, no particular 
time can be given for the occurrence of Cumacea in the plankton. They are found 
to be most abundant usually after a storm. D. quadrispinosa, which is reported to be 
abimdant in this region, was not taken during the past year. The following forms 
were taken in 1922-23: Cydaspis variens Caiman, Leptocuma minor Caiman, 
Oxyurostylis smithi Caiman, Diastylis polita Smith, and D. sculpta Sars. 
SCHIZOPODA AND STOMATOPODA 
The larval stages, and often the adxilts {Neomysis americana) of the Mysidse, 
at certain times of the year are very characteristic members of the Woods Hole 
plankton. The euphausiids, however, are "outside" forms and appear with other 
oceanic plankton only after southwest winds. 
The Mysidie, living among the eelgrass in shallow water, are not true pelagic 
animals, but an occasional adult may be carried into the net at any time. Certain 
species apparently never swim freely during the breeding season. Heteromysis 
formx)sa and a species of the genus Erythrops (new to the region) are examples of 
this type. The former species has been recorded for every month of the year. 
Neomysis americana, on the contrary, has a definite pelagic period and swarms 
in surface waters from December to April, inclusive. The larvae appeared during 
the last week of April in 1899 and 1900 and continued in small numbers until 
July, the yoimg being liberated in the form of the adults. In 1923 the first adult 
appeared on May 17. 
Adult euphausiids have been recorded at various times by Edwards, but none 
are permanent inhabitants of this region. Their occurrence will be better under- 
stood when the distribution of the various species off the coast is more fully worked 
out. Five species from the surface collections of 1898, 1899, 1922, and 1923 were 
identified. On December 12, 1898, after a hard soiithwest storm, two Thysanoessa 
inermis and one T. longicaudata were taken. There may be something in the 
occurrence of the former species to give a clue to its distribution. Ztmmer gives 
it a wide range. It is a cold-water form, extending from the Vineyard Sound to 
the Gulf of Maine in the North Atlantic, always being found within the 50-fathom 
line. Records made to date seem to indicate a northerly migration throughout 
the summer months. The specimens recorded from Woods Hole were taken on 
December 12. The Albatross found scattered individuals in the deeper parts of 
Vineyard Sound in late July and August. Bigelow found it most abundant north 
of Cape Ann in early July and on German Bank in August, with minor centers of 
abundance off Penobscot Bay and in the northeast corner of the Gidf during the 
