14 



Occurrence. Only a very limited number of specimens of this remarkable 

 form have hitherto come under my notice. They were taken at different times, 

 some off the west coast of Norway (Aalesund), some in the Trondhjem Fjord, 

 from rather considerable depths, down to 100 fathoms. Some apparently imma- 

 ture specimens were also picked out of a plankton-sample taken from deep 

 water, a fact that seems to prove that this form is not so absolutely confined to 

 the bottom, as is the case with the other species of this genus. 



Gen. 3. SunarlSteS, Hesse, 1867. 



Syn: Longipedina, W. Miiller. 



Generic Characters. Body very slender in form, with the anterior divi- 

 sion scarcely at all compressed, posterior cylindrical in shape. Cephalosome con- 

 fluent with the 1st pedigerous segment, lateral parts not completely obtpcting the 

 oral parts at the sides. Epimeral plates of the succeeding segments small, rounded. 

 Genital segment in female without any trace of a transversal subdivision, and 

 without lateral denticles. Anal opercle smooth. Caudal rami somewhat produced 

 and slightly divergent, apical setae about as in Longipedia. Anterior antennae 

 less robust and less arcuate than in that genus, 6-articulate, and clothed with 

 very slender, partly ciliated setae; those in male terminating in a very strong 

 clawed hand. Posterior antennae and oral parts very similar in structure to those 

 in Longipedia. Natatory legs, however, somewhat different: 1st pair of nearly 

 the same size and structure as the 2nd, inner ramus of the latter quite normal in 

 female, slightly transformed in male, the 2 posterior pairs of somewhat simpler 

 structure than the 2 anterior, and provided with unusually long and slender setae. 

 Last pair of legs in both sexes quite rudimentary. Ovisac double. 



Remarks. This genus was established in the year 1867 by the French 

 naturalist, Hesse, to include a peculiar Copepod found by him as a commensal in 

 the same shell with a kind of hermit crab. The genus Longipedina of W. Miiller 

 is unquestionably identical with that of Hesse. As indicated by the name pro- 

 posed by the former author, this genus is, indeed, nearly allied to Longipedia, 

 exhibiting, as it does, a very similar structure of both the antennae and the oral 

 parts. In other respects, however, it differs rather materially, as for instance in 

 the altogether normal appearance of the inner ramus of the 2nd pair of legs, the 

 rudimentary condition of the last pair of legs, and the presence in the female of 



