.58 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.60 



First antennae six- jointed ; second pair two- jointed, short, uncinate. 

 Maxillae minute, setose; maxillipeds elongate, slender, with small 

 terminal claws. Egg tubes long, eggs flattened but little. Four 

 pairs of biramose swimming legs ; no fifth legs. 



Generic characters of male. — Cephalothorax elliptical, wider than 

 the rest of the body ; second, third, and fourth thorax segments free; 

 fifth segment fused with the genital segment, narrower than the free 

 segments and short. Abdomen one-jointed; anal laminae much 

 longer than the abdomen, narrow-cylindrical. 



First antennae six-jointed; second pair very long, stout, and 

 tipped with strong curved claws. Mouth parts and swimming legs 

 like those of the female. 



Type of the genus. — Gongericola pallida P. J. van Beneden. 



KEY TO THE SPECIES. 



Two free segments the same width as the head; fourth legs much larger than 

 the others, without setae pallida Beneden, 1854 



Two free segments wider than the head ; fourth legs smaller than the others, 

 with setae gracilis (Milne Edwards), 1840 



Remarks. — The name Cycnus was preoccupied by Hubener for a 

 genus of Lepidoptera in 1816, and hence can not stand for a parasitic 

 copepod genus, as was stated by Norman.^^ Hence Beneden's name 

 must be adopted, and the type of the genus will be the species de- 

 scribed by him. 



Genus NEMESIS Risso. 



Nemesis Risso, Hist. Nat. des principales de I'Europe Meridionale, vol. 5, p. 



135, 1826. 

 Nemesis Rorx, Crustaces de la M6diterran6e, 1828, pi. 20, figs. 1-9. 

 Nemesis Milne Edwards. Histoire Naturelle des Crustaces, 1840, vol. 3, 



p. 486. 

 Pagodina Beneden, Bull. Acad. Roy. Eelgique, vol. 20, 1853, p. 482. 

 Nemesis Heller, Reise der Novara, Crustacea, 1865, p. 220. 

 Nemesis Valle, Boll. Soc. Adriatica Sci. Nat. Trieste, vol. 6, 1880, p. 66. 

 Nemesis Brian, Copepodi parassiti dei Pesci d'ltalia, 1906, p. 71. 



Generic characters of female. — Head fused with the first thorax seg- 

 ment, oval ; four free quadrilateral thorax segments, each carrying a 

 pair of biramose swimming legs, the first three as large as the cephalo- 

 thorax or larger. Genital segment much smaller ; abdomen narrower 

 than the genital segment, two- or three- jointed; anal laminae minute 

 and tipped with short spines. 



First antennae ten- to fifteen- jointed, filiform, setose; second pair 

 large, jointed, and ending in an exceptionally powerful claw. First 

 maxillae minute, rudimentary; second pair two-jointed, terminating 

 in a fleshy process. Maxillipeds very large, projecting their entire 



« Ann. Ma«. Nat. Hist., ser. 7, vol. 11, 1903, p. 369. 



