88 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.60 



name has become so widely known that it will be difficult to make the 

 requisite change. It is evidently cosmopolitan in distribution, being 

 found everywhere that the host occurs. The common sturgeon is not 

 only found in salt water, but it also runs up our rivers. Whether 

 these parasites remain upon the gills after their host enters fresh 

 water has not been determined, but they probably do. Strangely 

 enough out of the long list of investigators who have recorded this 

 parasite not a single one has mentioned that it was to be found in 

 fresh water. 



Genus CYBICOLA Bassett-Smith. 



Helleria Bassett-Smith, Ann. Mag. Nat. Hist., sen 7, vol. 1, 1898, p. 10. 

 CyUcola Bassett-Smith, Ann. Mag. Nat. Hist., ser. 7, vol. 2, 1898, p. 371. 



Generic characters of female. — Body elongate, without dorsal 

 plates. Head rounded, not fused with the first thorax segment, as 

 wide as the genital segment. First three thorax segments free, each 

 with a pair of soft lateral processes, the remainder of the body 

 fused into an elongate genital segment, which carries the long and 

 narrow anal laminae on its posterior margin. Egg strings longer 

 than the body, straight. 



First antennae seven- jointed, setaceous; second pair in the form of 

 strong claws with a single tooth on their inner margin. First 

 maxillae three-jointed, uncinate; second pair also three- jointed, 

 tipped with a short, curved claw dentate on its inner margin. Maxil- 

 lipeds two-jointed, the basal joint very large and powerful, its 

 outer margin undulate and fringed with bunches of fine hairs, the 

 terminal claw stout, strongly curved, with a single tooth on its inner 

 margin. Three pairs of rudimentary swimming legs, the first pair 

 biramose, the other two uniramose, all' the rami minute, one-jointed, 

 tipped with a seta. 



Generic characters of male. — Body shorter than in the female, 

 head more oval. No free thorax segments, but the entire thorax 

 fused with the genital segment; abdomen distinct with foliate anal 

 laminae whose tips are fringed with fine hairs. Antennae and mouth 

 parts like those of the female except that the maxillipeds are longer 

 and less stout. Only two pairs of swimming legs, the first pair 

 biramose, the rami broad, one-jointed and tipped with claws, the 

 second pair uniramose, the rami two-jointed and also tipped with 

 claws. 



Type of the genus. — CyhicoJa armata.^ monotypic. 



Remarks. — This genus was first named Helleria., but as that name 

 was already in use for a genus of crustaceans Bassett-Smith himself 

 changed it later in the same year. It has never been seen or men- 

 tioned by any other scientist. Its principal characteristics are the 

 absence of the third and fourth swimming legs in the male and of the 



