34 



BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



Genus RHINCALANUS Dana, 1852 



Head produced anteriorly into a conical process, which carries on 

 its ventral surface the rostral filaments; head fused with the first 

 segment; thoracic segments armed with small spines on their poste- 

 rior margins; urosome 3-segmented, the distal segment fused with 

 the caudal rami; first antennae much longer than the body; both 

 rami of the first legs 2-segmented, of the second, third, and fourth 

 legs 3-segmented ; fifth legs uniramose and 3-segmented. 



KEY TO THE SPECIES (BOTH SEXES) 



1. Anterior projection of head conical, entirely concealing the 

 rostral filaments in dorsal view ; fifth leg of female witli one 

 seta on second and three on third segment; right fifth leg of 



male tipped with a curved claw nasutus (p. 34) 



Anterior projection of head anchor-shaped, leaving the rostral 

 filaments visible dorsally ; fifth leg of female with one seta 

 on third segment and none on the second segment ; right fifth 

 leg of male with straight claw cornutus (p. 35) 



RHINCALANUS NASUTUS Giesbrecht 



Figure 18 

 Rhincalanus nasutus Giesbrecht, Fauna und Flora des Golfes von Neapel, vol. 

 19, p. 152, pis. 3, 9, 12, 35, 1892.— Sabs, Crustacea of Norway, vol. 4, p. 15, 

 pis. 6-7, 1901. 



Occurrence. — Two females from 

 trawl wings at Station 1032, Fish 

 Hamk; 30 males and females from 

 traAvl wings at Stations 2173, 2195, 

 2219, Albatross., south and south- 

 east of Nantucket. 



Distribution. — Western Medi- 

 terranean, southern Pacific (Gies- 

 brecht) ; northern Atlantic 

 (Cleve) ; Iceland, North Sea 

 (Sars) ; California coast (Es- 

 terly) ; Atlantic and Pacific Oceans 

 (Giesbrecht); Indian Ocean 

 (With); Chesapeake Bay (Wil- 

 son) ; Gulf of Maine (Bigelow). 



Color. — Eathbun wrote concern- 

 ing the two females taken at Sta- 

 tion 1032, Fish Eawh, " The larger 

 specimen with such extremely 

 long antennae was absolutely color- 

 less." Sars also said of this spe- 

 cies in the reference quoted above, 

 " Body highly pellucid, and almost without any pigment." On the 

 colored plate of Giesbrecht's monograph (pi. 3, fig. 6), the ovary and 



FiGUUE 18. — Rhincalanus nasutus: a. Fe- 

 male, dorsal ; b, fifth leg of female ; 

 c, fifth legs of male (r, right leg) 



