669 



Gen. ParacyamUS, G-. 0. Sars, n. 

 Syn. : Cyamus Liitken (part). 



Body moderately expanded in female, much more slender and also of 

 considerably larger size in the male. Cephalon completely fused together 

 with the 1st segment of mesosome. Superior antennae well developed, with 

 the flagellum uniarticulate. Inferior antennse very small, 4-articulate. An- 

 terior lip rather broad, bilobed; posterior lip with the inner lobes very nar- 

 row. Mandibles comparatively stout, without any molar expansion. First 

 pair of maxillse with the masticatory lobe armed with strong, denticulated 

 spines, palp not reaching to the end of that lobe, and densely clothed with 

 slender spines. Second pair of maxillae very small, issuing from a common 

 basal segment, inner lobe extremely minute and bisetose, outer one rounded 

 and setiferous. Maxillipeds with the palp rudimentary, uniarticulate. G-na- 

 thopoda very unequal, the anterior ones being much smaller than the posterior, 

 and partly concealed beneath them. Branchial appendages simple, elongated, 

 conically tapering. Pereiopoda very strong, hooked. 



Remarks. The present new genus is somewhat intermediate between 

 Cyamus and Platycyamits, agreeing with the former in the structure of the 

 gnathopoda, with the latter in the rudimentary condition of the maxillipeds. 

 Besides the species described below, the C. erraticns Rouss. & Vaux., as also 

 C. pacificns Lutken would seem to belong to this genus. 



Paracyamus boopis, (Liitken). 



(PI. 240). 



Cyamus boopis, Liitken, Biclrag til kundskaben om Arterne af 8l?egteii Cyamus; Danske Vid. 

 Selskab. Skrifter, 5th series, Vol. 10 p. 262, PI. Ill, fig. 6. 



Syn.: Oniscus ceti, 0. Fabr. (not Linne'). 



Body in female oblong fusiform in outline, with the branchiferous 

 segments much broader than the others, and firmly connected; in male much 

 more slender, nearly linear, with the branchiferous segments scarcely broader 

 than the others and, like those, having the lateral parts separated by rather 



88 Crustacea. 



