ABT. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WILSON 23 



stages became so abundant in January and February as to far out- 

 number the adults. Probably some of the development stages noted 

 during the present survey at various stations in the outer bay during 

 winter belonged to this species. Found by Sars both in the Nor- 

 wegian fiords and in the open ocean and believed to form an essential 

 part of the food of several pelagic fishes, such as the herring and the 

 mackerel. In Chesapeake Bay it is probably eaten also by the shad 

 during their spring migrations. 



CENTROPAGES TYPICUS Krjiyer 



CenU'opages typicus Kr0yer, Naturh. Tidsskrift, vol. 2 (new ser.), p. 588, p. 

 6, figs. 22-26, 1847.— G. O. Sars, Crustacea of Norway, vol. 4, p. 75, pis. 

 49-51, 1902. 



Occurrence. — Universally distributed throughout the bay and 

 found at nearly every station. It is essentially a winter species but 

 is probably present during the entire year. Like C. hamatus it was 

 taken in surface, bottom, and vertical nets and was present in large 

 numbers in the outside ocean. 



Remarks. — Given by Fish as one of the two pelagic species that 

 together form the bulk of the summer copepod fauna at Woods Hole. 

 In Chesapeake Bay it is just as typicall}^ a winter form, but is ap- 

 parently a summer species in the ocean outside the bay. Found in 

 both the open sea and the fiords of the Norwegian coast, often in 

 great abundance. Brady said tliat this species and C. hamatus were 

 so common in the North Sea and the Atlantic that few gatherings 

 were without them. 



EUCHAETA NORVEGICA Boeck 



Euchaeta noi-vegica Boeck, Christiania Videnskebeliger Selskabet Forhand- 

 linger, p. 40, 1872. — G. O. Saks, Crustacea of Norway, vol. 4, p. 38; pis. 

 24-26, 1902. 



Occurrence. — A few females of this species were taken in the bot- 

 tom net on the 100-fathom line in the outside ocean, but it was not 

 found anywhere within the bay. 



Remarks. — This is a northern pelagic species and according to 

 Bigelow occurs in most horizontal hauls deeper than 100 meters, 

 but only sporadically at higher levels. Probably the present record 

 is as far south as it has been obtained, and as it is an inhabitant of 

 deep water there is little likelihood that it will be found within the 

 bay. Sars found it particularly in the great depths of the fiords, 

 and probably one condition that keeps it from entering the bay is 

 the shallowness of the water. It is also possible that this copepod 

 can not accommodate itself as readily as some others to any consid- 

 erable change in salinity. 



