46 T. V. nOlMJSON. 



surface of the cephalosomc is sculptured in a peculiar way, but ouly ditfcriug in the 

 minutest detail from that of the type species, G. aniarcticus ; two flattened patches 

 occur behind the crescentic depressions of the anterior margin ; imnndiately behind 

 these is a transverse band more coarsely knobbed and posteriorly divided into iour 

 distinct tubercles, the outer ones being at least half as large again as the inner 

 ones. This entire sculptured area is separated off from the " lateral plate," where the 

 eyes are situated, by a conspicuous dermal fold, which reaches to about the centre of 

 the level of the eyes. 



The mesosome comprises the normal seven segments, and of these the fourth is 

 the largest ; the differences between any of them are, however, not great. All of 

 them show a mid-dorsal longitudinal ridge more or less strongly develojied. The 

 sculpturing comprises a roughly triangular patch, its apex directed to the middle line. 

 These patches are comparatively smooth on the third and fourth segments, but 

 increase in roughness anteriorly as well as posteriorly. 



The first segment arches forwards to partially enclose the cephalosome, a smooth 

 dermal ridge runs round this segment and forms its anterior margin to a certain 

 extent, but in front of it for a short distance either side the middle line is a thin band 

 of irregular .sculpturing. The three posterior segments are curved backwards, the 

 curvature increasing progressively to the last which, with its epimera, completely 

 hides the lateral margins of the two first segments of the metasome. 



The epimera are large, smooth, the first three having their angles rounded ; the 

 posterior angle of the fourth is pointed. The epimera of three posterior segments are 

 conspicuously se[)arated from the segment bearing them ; they Ijccome narrower, 

 longer, and more acute from first to last. 



In appearance the cephalosome and metasome are exactly like those of 

 G. antarcticus Eights, the only difference being one of proportion. 



The metasome comprises four free segments, visible dorsally, and a fifth, fused 

 with the urosome, and this last is the longest ; of the other four, the two middle 

 ones are subeiiual in length, as are the first and fourth, which are a little shorter. The 

 last segment of the me-^osome conceals the lateral margins of the first, and its epimera 

 hide, but not altogether, the diminutive epimera of the second .segment ; the epimera 

 of the other two segments progressively increa.se, the last being large and directed 

 backward.s. The urosome has the fifth .segment fused with it, and this irregularly 

 tuberculated, and has a prominent niid-dor.sal ridge ; the urosome itself is long, 

 comparatively slender, having a sinuous tapering margin and terminating in a strong 

 and rather lengthy spine, the end of a well-developed median ridge. 



^'entrally the fourth to sixth segments of the mesosome are conspicuously grooved 

 in the middle line, and traces of such a character occur on all. 



The oostegites are five pairs, and occur on the first segment to the fifth. In the 

 largest female, which is the specimen examined in det-ail, they are not fully developed, 

 and are strong ovoid structures which do not reach anvwhere near the mid-vcutral line. 



