144 



The poecilostomous Cyclopoida which up to the present are stated 

 to belong to the Fauna of Norway, may be referred to 6 well-defined families, 

 to be treated of in the succeeding pages. 



Fam. 10. Clausidiidae. 



Characters. Anterior division of body more or less expanded, having 

 the first trunk-segment wholly consolidated with the cephalon. Tail composed 

 of the usual number of segments. Anterior antennae 6 7-articulate. Poste- 

 rior antennas scarcely prehensile, being clothed at the tip with long curved 

 setae. Anterior lip short and broad, lamellar, with the terminal edge entire 

 and fringed with fine spinules. Maxillae with the terminal part only slightly 

 curved and armed at the tip with 2 stout claw-like spines distinctly articulated 

 at the base, and accompanied inside by one or two coarse ciliated setae; palp 

 generally well developed, incurved. Anterior maxillipeds short and stout, biar- 

 ticulate; 1st joint very massive, 2nd small and terminating- in 2 claw-like spines 

 accompanied by one or 2 ciliated setae. Posterior maxillipeds more slender 

 and 3-articulate, being generally clothed with rather long setae; those in male 

 very powerfully developed. Ventral face forming between the oral parts in 

 front 2 juxtaposed hairy lappets (lateral lips). Natatory legs, as a rule, of 

 normal structure, though the 1st pair in some cases (Clausidium) may be peculi- 

 arly modified. Last pair of legs uni- or bi-articulate, distal joint more or less 

 lamellar. 



Remarks. The present family was established by E. Canu, to com- 

 prise the genus Hersilia Philippi and allied forms. As however the generic 

 name Hersilia has been preoccupied, it must be replaced by the name 

 Clausidium proposed by Kossman, and the family accordingly be named 

 Clausidiidce instead of Hersiliidce. It is chiefly characterised, as compared 

 with the other families, by the non-prehensile posterior antennae, the form of 

 the anterior lip, the peculiar armature of the maxillae, and partly also by the 

 structure of the maxillipeds. To the Norwegian Fauna belong 2 well-defined 

 genera referable to this family, each represented by only a single species. 



