8_ 



posterior antennae and oral parts, now with quick leaps effected by powerful 

 strokes of the natatory legs and the urosome. It keeps constantly close to the 

 bottom. 



Distribution. English and Scottish coasts (Brady, Scott), Gulf o Naples 

 (Giesbrecht). 



Fam. 2. Longipediidae. 



Characters. Body of normal appearance, more or less cylindrical in form, 

 with no sharp demarcation between the anterior and posterior divisions. Cepha- 

 losome in some cases distinctly defined from the 1st pedigerous segment; rostrum 

 lamellar and movably articulated to the cephalic shield. Eye well developed. 

 Anterior antennae short and stout, consisting of a very limited number of articu- 

 lations densely clothed with partly spiniform setae. Posterior antennae with the outer 

 ramus very fully developed, cylindrical, 6- or 7-articulate. Mandibles and maxillae 

 with well-developed and abundantly setiferous palps. Anterior maxillipeds calanoid 

 in structure ; posterior ones very delicate, lamellar, and fringed with densely plumous 

 setae. Natatory legs with both rami 3-articulate and rather narrow, being armed 

 outside with strong spines, inside and at the tip with long, partly spiniform setse; 

 1st pair not differing greatly from the others. Last pair of legs with the inner 

 expansion of the proximal joint very small, distal joint well-developed or rudi- 

 mentary. Ovisac single or double. 



Remarks. In this family I propose to comprise the 3 genera Longipedia 

 Glaus, Sunaristes Hesse and Canuella Scott, which are undoubtedly closely allied, 

 and together form a natural group of the Achirota. It does not answer to the 

 subfamily Longipediina} of Brady, to which a much wider range is given, also com- 

 prising, as it does, the genera Zosime, Ectinosoma and Bradya, which in my 

 opinion ought to be referred to other families. The most characteristic features 

 of the present family are the unusually full development of the outer ramus of the 

 posterior antennae, the likewise largely-developed palps on the mandibles and 

 maxillae, and, finally, the peculiar, delicate structure of the posterior maxil- 

 lipeds. In all these characters there is a great similarity between the 3 above- 

 named genera, whereas in other respects well-marked differences between them 

 are found to exist. 



