COPEPODS OF THE WOODS HOLE REGION" 



163 



of genital segment and first abdominal segment covered with trans- 

 verse rows of minute hairs ; second segment of fifth legs longer than 

 wide ; end segment swollen at the base, acuminate distally and armed 

 with minute hairs, but without teeth, the same length as the plumose 

 seta on the second segment. Total length, 1-1.25 mm. 



Male. — As long as the female but narrower ; urosome 5-segmented, 

 the penultimate segment well defined; second free segment of the 

 right fifth leg with a deep invagination at the center of the inner 

 margin, and proximal to it a stout spine; end segment of the left 

 fifth leg with a terminal spine and a stout, angular process on the 

 inner margin close to the tip. Total length, 1-1.25 mm. 



Remarks. — According to Fish this species apparently disappears 

 about the first of July and does not reappear until December. It 

 may be recognized by the lack of teeth on the end segment of the 

 fifth legs in the female, and by the 

 invagination and angular process 

 on the fifth legs of the male. 



ACARTIA DISCAUDATA (Giesbrecht) 

 Figure 111 



Bias discaudatus Giesbrecht, Vierter 



Ber. Coram. Uuters. Deutsch. 



Meere, Jahrg. 7, p. 148, pis. 3, 5, 



8, 9, 1882. 

 Acartia discaudata Sars, Crustacea of 



Norway, vol. 4, p. 152, pi. 102, 1903. 



Occmn^ence. — Two females 

 from small pond on eastern 

 shore of Buzzards Bay in Fal- 

 mouth near Quisset Harbor. 



Distribution. — Baltic Sea 

 (Giesbrecht) ; British seas (T. 

 Scott) ; French coast (Canu) ; Norwegian coast (Sars) ; Helgoland 

 (Claus) ; Kieler Fohrde (Giesbrecht) ; Gulf of Finland (Braun) ; 

 Irish coast (Thompson) ; Boulogne sur Mer (Du Guerne). 



Color. — ^^Body a light bluish gray, semitransparent, and without 

 pigment marks. 



Female.— lA.^2iA separated from the first segment ; fourth and fifth 

 segments fused, with rounded corners; genital segment much dilated 

 across its anterior portion, with a large ventral protuberance twisted 

 to the left ; anal segment widened distally to support the large caudal 

 rami, which are swollen into rounded bulbs, as wide as lonff, with 

 the bases of their terminal setae considerably dilated ; end segment of 

 fifth legs as long as the seta on the preceding segment, enlarged 



FiGDRE m. — Acartia discaudata: a, Fe 

 male, dorsal (after Sars) ; b, female, fifth 

 legs ; c, male, fifth legs 



