ABT. 15 COPEPOD CRUSTACEANS OP CHESAPEAKE BAY WILSON 25 



LABIDOCERA WOLLASTONI (Lubbock) 



Pontella wollastoni Lubbock, Ann. Mag. Nat. Hist., ser. 2, vol. 20, p. 406, pis. 



10,11, 1857. 

 Labidooera wollastoni G. O. Saks, Crustacea of Norway, vol. 4, p. 142, pis. 95., 



96, 1902. 



Occurrence. — Ten specimens of this species, including both sexes, 

 were obtained in a surface net at Station G, August 22, 1920. 



Remarks. — The single occurrence and limited number of this 

 species make it a rare copepod in the plankton of the bay and of no 

 economic value. It has never before, however, been reported from 

 our American coast, as all Giesbrecht's specimens came from the 

 western Atlantic. Sars considered it " like all the other Pontel- 

 lidae, a true pelagic form, occurring more generally in the open 

 ocean, close to the surface of the sea " (p. 143). 



MECYNOCERA CLAUSII I. C. Thompson 



Mecynocera clausii Thompson, Jouru. Linnaean Soc. London, voL 20, p. 146. 

 pi. 11, figs. 1-4, 1888.— Wheelee, Bull. U. S. Bur. Fisheries, vol. 19, p. 168, 

 fig. 5, 1899. 



Occurrence. — About 150 specimens of this species were obtained 

 in the bottom net at the 100-fathom line outside the bay. 



Retnarks. — This is another distinctly pelagic copepod and southern 

 in its habitat. It is very transparent and colorless and is hence easily 

 overlooked unless carefully searched for. The exceptionally long 

 first antennae are very buoyant, and, when stretched out at right 

 angles to the body axis, they hold the copepod in suspension, some- 

 times even after preservation. It is not likely to be found inside 

 the limits of the bay. T. Scott ^ reported this copepod from 16 

 of the tow-net gatherings, the deepest of which came from a depth 

 of 235 fathoms. 



METRmiA LUCENS Boeck 



Metridia lucens Boeck, Christiania Videnskebelige Selskabet Forhandlinger, 

 p. 238, 1864.— G. O. Saks, Crustacea of Norway, vol. 4, p. 113, pi. 77, 1902. 



Occurrence. — Taken in large numbers in the bottom net during the 

 trip to the 100-fathom line at depths of 40 and 118 fathoms. 



Remarks. — Wheeler secured but a single specimen at Woods Hole 

 in summer, but Fish found it a very common form in winter and 

 spring. If it comes into the harbor at Woods Hole so freely at that 

 season of the year, it would seem possible at least that it may enter 

 the outer portion of Chesapeake Bay during the same season. This 

 species is luminous and gives off a brilliant blue-green light when 

 disturbed. During the spring before the summer plankton has 



"^ Report on Entomostraca from the Gulf of Guinea, collected by John Rattray, B. Si- 

 Trans. Linn. Soc. London, ser. 2, vol. 6, pt. 1, Zoology, 161 pp., 15 pis., 1894. 



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