COPEPODS OF THE WOODS HOLE KEGIOIT 



127 



Male. — Smaller than the female; urosome symmetrical and very 

 slender; left first antenna geniculate; endopod of both second legs 

 invaginated; fifth legs very asymmetrical, 5-segmented, left leg 

 longer and narrower than the right; end segment of the latter much 

 widened, laminate and securiform; basal segments of first antennae 

 armed with flattened, spatulate aesthetasks; luminous organ on the 

 right side. Total length, 3-3.5 mm. 



Remarks. — The large size, the symmetry of the urosome in both 

 sexes, and the reversal of the fifth legs in the male are the chief char- 

 acters of this species. 



PLEUROMAMMA GRACILIS (Glaus) 

 FiGUBE 85 



Plcuromtna, gracile Claims, Die frei lebenden Copepodeu, p. 197, pi. 5, 18G3. — 

 GiESBKECHT, FauiiR uiid Flora des Golfes von Neapel, vol. 19, p. 347, pis. .5, 

 32, 33, 1892. 



OccmTence. — Two females in surface tow south of Gay Head, Sep- 

 tember, 1883; 1 female in surface tow on Georges Bank, September, 

 1872; 25 males and females from 

 trawl wings, Station 2195, Albatross. 



Distribution. — Nizza, Messina 

 (Glaus) ; North Atlantic (Cleve) ; 

 tropical Atlantic (Giesbrecht) ; In- 

 dian Ocean (Giesbrecht) ; Gulf of 

 Guinea (T. Scott) ; Mediterranean, 

 Red Sea, Indian Ocean (Thompson 

 and Scott) ; Adriatic (Steuer, Pesta) ; 

 Malay Archipelago (A. Scott) ; Cali- 

 fornia coast (Esterly) ; Gulf of Maine 

 (Bigelow). 



Color. — Body in general colorless 

 and fairly transparent, with scattered red pigment ; a narrow red line 

 starts in the cephalon just above the mouth and runs backward along 

 the median line to the first thoracic segment; another reddish line 

 runs transversely along the anterior margin of the fourth segment, 

 and there is a reddish spot above the rectum in the anal segment; 

 the forehead, the skin glands, the area around the genital openings, 

 and the dorsal surface of the caudal rami are greenish yellow; the 

 luminous organ is dark reddish brown; the eye is dark ruby red 

 (Rathbun). 



Female. — Head separated from the first segment; urosome half as 

 long as metasome ; genital segment longer than both abdominal seg- 

 ments combined, swollen ventrally; fifth legs 4-segmented, the same 

 diameter throughout and tipped with three stout spines, the inner of 

 which is the shortest; the two distal segments of these fifth legs are 



Figure 85. — Pleuromamma gracilis: 

 a. Female, fifth legs ; h, male, fifth 

 legs 



