474 G. 0. SARS, [t. XIII 



2. Pseudocuma Sowinskyi, G. 0. Sars, n. sp. 

 (Pi. ni). 



Specific Characteristics Ç. — Very like the preceding species in its outward 

 appearance, though perhaps a little more slender. Carapace with the bran- 

 chial regions much swollen and evenly rounded above, with a low coarsely 

 serrated crest running along their most prominent part, and continued ante- 

 riorly on each side of the gastric region as far as the tip of the pseudo-rostral 

 projection ; the latter very short and subtrnncated at the tip ; antero-lateral 

 corners very much projecting, and having their anterior edge coarsely ser- 

 rated. All the free segments of mesosome distinctly keeled dorsally, the keel 

 being elevated in the 3 anterior segments to comparatively small rounded 

 projections, in the 2 posterior segments to somewhat larger laminar pro- 

 minences, that of last segment the most projecting and triangular in form; 

 edge of the projections coarsely serrated. Segments of metasome without 

 any keels dorsally. Ocular lobe rounded triangular, with the visual elements 

 less distinct, the median cornea being inconspicuous. Antennae, oral parts, 

 and legs nearly as in the preceding species. Uropoda, on the other hand, 

 comparatively much shorter, not nearly attaining half the length of the 

 metasome, scape scarcely longer than the rami; the latter equal-sized, and 

 without any spinules on the inner edge. Telson transversely quadrangular. 

 Length of adult female reaching 11 mm. 



Remarks. — Though very nearly related to the preceding species, this 

 form may, on a closer examination, be readily distinguished by several well- 

 marked characteristics. For instance the carapace differs in the distinct 

 serrated crests running along the branchial regions and continued along the 

 sides of its anterior part, in the considerably inferior size of the pseudo-rostral 

 projection, and in the greatly-projecting antero-lateral corners, the anterior 

 edge of which is coarsely serrated. Moreover the dorsal projections of the 

 mesosome are far less prominent, and the 2 juxtaposed dorsal prominences 

 occurrring in P. pectinata are replaced by a single median projection of in- 

 ferior size. Finally the metasome is more elongated, and the uropoda consi- 

 derably shorter than in that species. Only female specimens have hitherto 

 come under my inspection. 



Description of the female. 



The length of adult ovigerous specimens amounts to 1 1 mm., and this 

 form thus attains a still larger size than the preceding species, and is in 

 jact the largest of the hitherto known Caspian Cumacea. 



The general form of the body (see figs. 1 and 2) resembles that of 

 P. pectinata, though being perhaps somewhat more slender, and thus cor- 



Bulletin N. S. IV (XXXYI) p. 310. 



