HANSEN: THE ISOPODA. 113 



free space. The labium (c) is tolerably small, a little broader than the hypo- 

 pharynx, the posterior margin emarginate. The hypopharynx (h) with the 

 lateral margins sub-parallel. Mandibles (d), maxillulse (e), and maxillae (/) 

 scarcely need special mention, their general shape and position being easily seen 

 in Fig. 1 b. In this figure the place of attachment of the maxillipeds is lettered 

 with g. The left maxilliped, seen from below, is shown in Figure 1 c ; the first 

 joint (1) with its usual free posterior dilatation, the second joint (2) with the 

 exterior dilatation (d'^) which is of secondary origin — as in the females of the 

 family Cymothoidse — and cannot be considered as an exopod ; the palp {p) is 

 longer than in the following forms, but not distinctly jointed. The peculiar 

 border behind the attachment of the maxillipeds is well developed, having on 

 each side two oblique, good-sized rather broad, but not long, somewhat fleshy, 

 lamellar processes (Fig. 16, /). 



Thorax. On the four anterior segments the ovarian bosses are well developed, 

 occupying but a little more than half the length of the sub-marginal part of 

 each segment ; in the other segments the bosses are wanting. The pleural 

 plates (" lames pleurales " of Giard and Bonnier) of the four anterior segments 

 are interesting : each of them is divided by a deep incision into two portions, 

 the anterior of w'hich is oblong, set off by a furrow and especially on the right 

 side of the animal incised or emarginate exteriorly, while the posterior forms 

 a shorter, rounded, not defined lobe. In the three posterior segments the pleural 

 plates are larger and laterally more prominent, but neither divided nor set off. 

 The ventral side of the two posterior segments is elevated and divided by nu- 

 merous longitudinal ridges into low fleshy lamellae; the other segments possess 

 a similar, but more narrow, transverse keel divided into small protuberances. 

 The legs are normal, each sitting on an eminence which often is rather promi- 

 nent (its appearance on the left side of the figure conveys the impression that 

 the leg has a short basal joint, which of course is not the case) ; the second 

 joint (basipodite, Giard and Bonnier, the basal joint being fused with the 

 segment) not expanded ; the claw is present, and none of the joints with keels 

 or rugosities. The first left leg with its marsupial plate is exhibited in Figure 

 1 d, which, better than a long description, will show the differences between the 

 plate in this and in the following forms ; the transverse furrow on its exterior 

 side is plainly seen, and on the inner side is found a transverse keel, the proxi- 

 mal part of which is divided into a few lameHse. The margins of the marsupial 

 plates are more or less hairy; on the anterior margins of all plates the hairs are 

 fewer and rather rudimentary, while especially the inner and posterior margin 

 of the two posterior pairs of plates is densely set with rather short hairs (omitted 

 in Fig. 1 a). (The marsupium was empty.) 



Abdomen. The segments are distinctly separated on the dorsal side. The 

 five anterior segments, all comparatively broad, on each side produced as good- 

 sized free plates, which mostly are cut off in a more or less oblique direction ; 

 on the left side all these pleural plates are bent obliquely upwards. The ventral 

 side of these segments shows a similar but less regular division into low lamellae 

 as that of the posterior thoracic segments. The pleopods of medium size, each 



