82 



flagellum much shorter than the peduncle, and rather thick, being composed, in 

 female, of 7, in male, of 9 articulations only. Legs in both sexes very strongly 

 built, those in male having, inside the outer joints, a dense fringe of delicate cilia. 

 Second pair of pleopoda in male with the stylet reaching beyond the inner plate. 

 Uropoda rather broad, with the terminal plate blunted at the tip. Colour some- 

 what variable, more or less dark brownish, with irregular shadows of a darker 

 hue. Length of adult female 9 mm., of male 13 mm. 



Remarks. — There cannot be any doubt that this is the true /. pelacjica 

 of Leach, and that the form at first described by H. Eathke as I. brevicomis and 

 subsequently named by him I. torosa, is the very same species. By recent authors 

 this form has generally been regarded as only a variety of I. baltica; but I 

 believe that in doing so, they cannot have examined the true Leachian species, 

 which it is impossible to confound with I. baltica. As will appear from the 

 figures here given, this form is in fact a very distinct and easily recognizable 

 species, well distinguished in both sexes by its short and stout body, the small 

 coxal plates, the short and robust inferior antennae, and the unusually strongly 

 built legs. Moreover, the terminal segment of the metasome' exhibits a form 

 rather different from that in the other Norwegian species. 



Occurrence. — Eathke found this form at Christiansund among Mytilus 

 growing close to the shore. I have myself taken it in another locality, viz. out- 

 side Lillesancl, south coast of Norway, where it occurred likewise close to the 

 shore, among algas. 



Distribution. — British Isles (Leach, Sp. Bate), coast of France (Bonnier). 



3. Idothea granulosa, Ratlike. 



(PI. XXXIV, fig. 1.) . 



Idothea granulosa, Eathke, Beitrage zuv Fauna Noi-wegens, p. 23. 



Specific Characters. — Body oblong oval, somewhat more than 3 times as long 

 as it is broad, with the dorsal face distinctly, granular being covered with small de- 

 pressed pits. Coxal plates comparatively small, not contiguous. Metasome in male 

 comparatively longer than in female, equalling in length the 6 posterior segments of 

 mesosome combined, terminal segment in both sexes considerably attenuated, lan- 

 ceolate, terminating in a rather prominent conical projection, lateral corners rounded 

 off. Eyes of moderate size. Superior antennae with the last joint of the peduncle 

 about the length of the 2nd. Inferior antenna? a little longer than in I. pelagica, 

 though scarcely reaching to the end of the 2nd segment of mesosome, flagellum 

 not attaining the length of the peduncle, comparatively narrower than in the said 



