AKT. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WILSON 37 



striking character, and the color remains in some of the preserved 

 specimens. This furnishes a quick method of distinguishing the 

 species from others of the genus, and the distinction can afterward 

 be verified by an examination of the fifth legs. 



HARPACTICUS CHELIFER (O. F. Muller) 



Cyclops cJielifcr O. F. Muixer, Zoologicus Dauaae Protliomus, p. 2913, 1776; 



Eutomostraca, p. 114, pi. 13, figs. 1-3, 1785. 

 Harpacticus ohelifer G. O. Saks, Crustacea of Norway, vol. 5, p. 49, pis. 27, 28, 



1904. 



Occurrence. — Only two females of this species were taken, at 

 Station G in a surface net December 4, 1920. 



Remarhs. — This is a northern form, littoral in habit, and hence 

 is likely to occur in any numbers in the bay. It can be recognized 

 at once by the enormous chelae on the maxiilipeds, which are much 

 larger than those of other species of the genus. Sars recorded it as 

 found in " quite shallow water close to the shore among algae, and 

 not infrequently left in tidal pools together with other littoral spe- 

 cies." From the distribution given by various authors this is an 

 extremely cosmopolitan species, appearing in nearly every sea and 

 ocean. 



HARPACTICUS GRACILIS Glaus 



Harpacticus gracilis Claus, Die frei lebenden Copepoden, p. 135, pi. 19, flg. 

 20, 1863.— G. O. Sars, Crustacea of Norway, vol. 5, p. 52, pi. 30, 1904. 



Occurrence. — Widely distributed throughout the bay but more 

 abundant in the inner portion. Taken most frequently at the sur- 

 face and in the winter, but lasting into spring and sometimes into 

 summer. Nowhere found in sufficient numbers to constitute more 

 than 1 or 2 per cent of the total haul, and usually much less than that. 



Remarks. — In spite of the wide distribution of this copepod 

 throughout the bay, the small numbers found at each station prevent 

 it from becoming of much importance in the economy of the plank- 

 ton. It does help, however, by its continued presence through most 

 of the year, and contributes its quota toward the food supply. It 

 is a littoral form and was reported by both Sars and Brian as found 

 in comparatively shallow water among algae. As far as known it 

 has not before been reported from our American coasts. 



HARPACTICUS LITTORALIS G. O. Sars 



Harpacticus chelifer Brady, British Copepoda, vol. 2, p. 146, pi. 64, figs. 19-20; 



pi. 65, figs. 1-15, 1880. 

 Harpacticus littoralis G. O. Sars, Crustacea of Norway, vol. 5, 363, suppl. 



pi. 8, 1910. 



Occurrence. — About 40 specimens of this species were obtained 

 in a surface net at Station R' on December 8, 1920, and a few 

 stragglers were also taken at Stations S and T. 



