412 



PROCEEDINGS OF THE \ 177o\ 1/, MUSEUM. 



vol. 38. 



Genus METRIDIA Boeek, 1864. 



METRIDIA LUCENS Boeck. 



Paracalanus hibernicus Brady and Robertson, Ann. Mag. Nat.JIist. (4), vol. 



12, is:;;, p. L26. 

 Metridia hibernica Giesbrecht, Fauna und Flora des Golfes von Neapel, vol. 19, 



L892, p. 340, figs. 2, L2, 16, 22, 28, 36,39.— Whim er, Bull. U. S. Pish.. Comm., 



vol. !!». 1900, p. 17(1, figs. a-f. 

 Metridia Incus Boeck, Forh. Vid. Selsk. Christiania, 1864, p. 14.— Giesbrkcht 



and Schmeil, Das Tierreich, Dec. 1898, p. 106. — G. 0. Sars, Crustacea of 



Norway, vol. 4, Calanoida, 1903, p. 113. 



Length— Female, 2.45 to 2.85 mm.; male, 2 mm. 



Occurrence. — Found in tow at Plymouth Harbor, August, and at 

 Woods Hole, December (Wheeler). 



Distribution. Mediterranean Sea, North Atlantic and Pacific 

 oceans; Gulf of ^uv/.. 



Genus PSEUDODIAPTOMUS Herrick, 1884. 



PSEUDODIAPTOMUS CORONATUS Williams. 



Pst udodiaptomus coronatus Williams, A.mer. Nat., vol. 40, 1906, p. 641, figs. 1-7. 



Length. — Female, about 1.5 mm.; male. 1.2 mm. 

 Characters. Abdomen of male, five-segmented; of female, four- 

 seemented. First segment of abdomen of female much swollen and 

 with many spines and bristles arranged in irregular patches, and with 



a pair of small spatnlate flaps extending 

 overthegenitalorifi.ee. Left side of sec- 

 ond segment of abdomen has a small de- 

 pression Idled with coarse bristles. Fifth 

 legs of female (fig. 4a) four-segmented, 

 with heavy terminal claws; of male, as in 

 fig. 46. 



The females are commonly with two 

 egg-sacs, the right one usually the smaller 

 of the two, and containing an average of 

 but two eggs. Occasionally the egg sacs 

 are about equal in size, and one female was 

 found in Eel Pond, Woods Hole, with but 

 one large oval egg sac. 

 Remarks Many of these interesting Calanoids were noted in 

 copula. The male clasps the female in a manner quite different from 

 that commonly observed among the Harpacticoida, in that they seem 

 always to unite with their anterior extremities pointed in exactly 

 opposite direct ion-, with th(> abdominal extremity of one or the other 

 pointed to one sWe at an angle. 



FlO. I. PSEXTDODLVPTOMtrS CORONA, 



i ii FOOT OF FEMALE X 



L75; b, FIFTH FOOT OF MALE X 150 



> ti.i; \\ ii.i.ivm 



