478 G. 0. SARS, [t. XIII 



The carapace is rather large, nearly equalling in length the exposed 

 part of the trunk and the first 2 segments of metasome combined. Its supe- 

 rior face (see fig. 2) is but little arcuate, declining with an even slope an- 

 teriorly. As seen from above (fig. 1), it appears somewhat instricted in the 

 middle, and has its greatest breadth quite posteriorly. The branchial regions 

 are but little swollen, and have each, in the middle, a distinct fold descend- 

 ing obliquely along the sides. Above, they are sharply marked off from each 

 other by a distinct crest running along their most prominent part, and con- 

 tinued in front as a short oblique fold defining them from the gastric region. 

 Quite posteriorly they are, moreover, defined by another fold running close 

 to the posterior edge of the carapace, and thus the sides of the carapace 

 have the appearance of being moulded in 3 parallel oblique folds. The 

 gastric area has the usual form, and is continued backwards as a narrow 

 wedge-shaped space lying between the branchial regions (see fig. 1). The 

 ocular lobe exhibits a somewhat unusual form, being very narrow triangular, 

 or nearly conical in shape. The pseudo-rostral projection is exceedingly promi- 

 nent, nearly horizontal, and acuminate at the tip, being defined below by an 

 angular notch. The antero-lateral corners project but little, and are nearly 

 rectangular, with the anterior edge slightly serrate. The inferior edges of 

 the carapace are rather curved in the middle, and join the posterior edge 

 without any distinct demarcation. 



The free segments of the mesosome are all distinctly keeled, as in P. 

 Soivinskyi, and their dorsal projections of much the same appearance as in 

 that species, except that their edges are smooth, not serrate. 



The metasome scarcely exceeds in length the anterior division of the 

 body, and has the segments of the usual shape, without any dorsal keels or 

 projections. 



The eye has the visual elements imperfectly developed, exhibiting only 

 2 small, juxtaposed pigmentary patches. 



As regards the antennas (fig. 3), oral parts, gnathopoda (figs. 4 and 5) 

 and legs (figs. 6 — 9), I do not find it necessary to describe them in detail, 

 as on the whole they agree in their structure with those parts in the 

 2 preceding species. 



The uropoda (see fig. 10) are comparatively short and stout, scarcely 

 exceeding in length % of the metasome. The scape is rather clumsy, and 

 only provided with a few (about 4) small bristles inside. The rami are nearly 

 equal- sized, and about the length of the scape, both mucroniform in shape 

 and terminating in a strong spine. The inner edge is minutely serrulate, and 

 has besides a small seta, which, on the inner ramus, is attached somewhat 

 beyond the middle, on the outer one, close to the apex. 



Bulletin N. S. IV (XXXVI) p. 814. 



