CYCLOPOIDEA. 1Q99 



OlTHONA PLUMIFERA, Baird. 



Antennas anticce late (130°) divaricatce, fere corporis longitudine, 7-arti- 

 cidatos, articulis secundo quarto et duabus ultimis brevioribus, setis 

 longissimis. Seta pedium biremium externa grandis, eleganter plumi- 

 formis. Abdomen b-ai^ticidatum, cephalotliorace longius, segmento lnio 

 pei'brevi, setas basales duas longiusculas rectos dimidio inaiquas 

 gerente. Styli caudales tenues, setd externa fere styli longitudine. 



Anterior antennae widely divaricate (130°) , nearly as long as the 

 body, seven-jointed, second, fourth, and last two segments shortest; 

 setae very long, some exceeding half the length of the antenna; 

 external seta of the natatory legs elegantly plumiform. Abdomen 

 five-jointed, longer than cephalothorax, the first segment very short, 

 bearing two unequal straight setae, one about half the length of the 

 other. Caudal stylets slender, divaricate, the external as long as 

 the stylet. 



Plate 76, fig. 4 a, animal, enlarged ; a', position of the antennae in 

 a specimen collected, May 16, 1842 ; b, imperfect view of posterior 

 antennae ; c, maxillipeds ; d, anterior feet ; e, natatory. 



Abundant in the Atlantic, October 22, 23, 24, 26, 1838, latitude 

 4£°-7° north, longitude 20°-22° west; also, taken May 16, 1842, 

 latitude 1° south, longitude 30° 30' west; also, probably the same in 

 the Pacific, among the Kingsmill Islands, April, 1841. 



Length, one-twentieth of an inch. Colour, reddish orange, or orange- 

 yellow ; the lateral plumes and some of the plumose setae of the 

 antennae of the same colour. This is a remarkably elegant species, 

 under the microscope. The four coloured plumes are alluded to in 

 Baird's specific name of this species. 



The three posterior segments of the cephalothorax are about one- 

 third the whole length. The second joint of the abdomen is a 

 little longer than the following (which are subequal), and it is a 

 little enlarged at base. The anterior antennae diverge at an angle of 



