HANSEN: THE ISOPODA. 101 



pulchra, the fifth almost as large as the fourth, and its inner margin partly 

 serrated; sixth and seventh joints much broader than in the preceding species. 

 The epipod with the exterior margin evenly curved. 



Thorax. It was badly preserved, and therefore the relative breadth of the 

 segments could not be drawn with so much certainty as could be wished. The 

 want of processes and the scabrous surface are mentioned above. The three 

 posterior segments, without any median dorsal impression not connected immov- 

 ably with each other, and somewhat shorter than the four others together ; the 

 last segment seems to be movably united with the abdomen. 



Thoracic Legs. The basal joint of the four anterior pairs anteriorly or ex- 

 teriorly produced into an angle or short scabrous process. The first pair (Plate 

 II. Fig. 1) rather short and stout ; the fifth joint conspicuously shorter than the 

 second, compressed and somewhat expanded on the under side, the margin of 

 which is hairy. Of the six other pairs of legs only the basal joint is preserved. 



Abdomen. It is nearly ovate and proportionally large compared with the 

 thorax, but neither shape nor magnitude could be drawn with absolute cer- 

 tainty, as the abdomen was roughly handled. The basal segment is very short; 

 for the rest only a pair of very faint somewhat curved longitudinal impressions 

 are seen on the scabrous dorsal surface. The operculum in the female without 

 any keel. 



Uropods. Somewhat longer than in the preceding species, but of about the 

 same shape. 



Size. The specimen described is about 25.6 mm. long, and 8.4 mm. broad. 



Habitat. Station 3413 (Lat. 2° 34' X., Long. 92° 6' W.), 1360 fathoms^ 

 1 specimen. 



Remarks. It is easily distinguished from all other large species hitherto 

 known by the general shape of thorax and abdomen, and the want of processes^ 



CYMOTHOID^. 



As to the limitation and the constituent elements of this family I refer tO' 

 the above named report on the Isopoda of the German Plankton Expedition. 

 Of its six sub-families only two, namely, ^giuse and Cymothoinse, are repre- 

 sented in the collection, the first sub-family by six, the second by one species. 

 The leading work on these two sub-families is Shiodte and Meinert: Symbolse 

 ad Monogr. Cymothoarum, Crust. Isopod. Familia (Naturh. Tidsskr., 3 R., 

 Bd. XII -XIV., 1879-84), and further remarks on the structure of the mouth 

 and the classification are found in my above named work, Cirolanidse, etc. 



In the large genus yEga Leach, not rarely several species are closely allied 

 to one another, and three of the four species established here differ only in small 

 features from species living in the most northern part of the Atlantic (in Nor- 

 way, Greenland, etc.). In the following, some characters derived from the 

 structure of the thoracic legs, and partly overlooked by earlier authors, will be 

 used; besides, the shape of the posterior angles of the thoracic " epimera," of 



