20 



32 or 33 mm. long from apex of rostrum to tip of telson, the length of the carapace, measured 

 in the middle line, being one-third that of the abdomen-, the males are but little, 2 or 3 mm., 

 shorter. The carapace of the male, which, like that of the female, is deeply emarginate 

 posteriorly, appears, when measured in the middorsal line, one and a half as long as high, the 

 carapace presenting its greatest height just in front of the posterior emargination ; it is smooth 

 and shining and regularly rounded dorsally. The rounded upper border appears, in a lateral 

 view, usually slightly convex, running obliquely downward to the tip of the rostrum, but 

 sometimes quite straight and in one specimen the gastric region appears, just behind the rostrum, 

 even slightly depressed ; the acuminate rostrum that reaches to the middle of the corneae of 

 the eye-peduncles, or almost to the distal end of the latter, is obtusely and indistinctly carinate 

 above and commonly slightly turned downward, while in those specimens, in which the dorsum 

 is straight, it runs horizontally forward. In some individuals the tip of the rostrum is slightly 

 curved upward. From the outer orbital angle which is rounded, the anterior border of the 

 carapace runs slightly forward and downward and passes with a regular curve into the lower 

 border; a little behind that border one observes a fine, short, longitudinal groove, separating 

 the gastric from the hepatic region ; the cardiac region which passes into the gastric, is 

 sometimes defined on each side by a fine, longitudinal, shallow groove from the branchial 

 regions, but often this groove is not developed at all. The margin of the posterior emargination 

 is flattened and more or less distinct from the upper surface of the carapace. 



In the female (Fig. "je) the median carina appears in the middle of the carapace com- 

 pressed, though obtuse and low, along a distance of about 1,5 mm.; this narrow compressed 

 part widens at the anterior third of the carapace and tapers then to the extremity of the rostrum 

 and this widened anterior part of the carina is rounded. In the same manner the compressed 

 median part of the carina gradually widens backward to the depressed margin of the posterior 

 emargination and is here also rounded. The lateral carinae arise from the orbital margin just 

 behind the eyestalks, run at first parallel or converge even a little backward nearly to the 

 level of the middle of the compressed part of the median carina, but then slightly diverge 

 backward to near the flattened border of the posterior emargination : in some specimens the 

 lateral carinae are therefore straight, while in other ones they appear slightly concave on their 

 anterior third. The lateral carinae are rather narrow, low, though blunt on their anterior 

 third, but gradually widen backward and are here rounded. The two grooves by which the 

 lateral carinae are separated from the median one, are shallow anteriorly and posteriorly, 

 but somewhat deeper near the middle ; the lateral carinae are also bounded on the outer side 

 by a shallow depression to near the posterior margin of the carapace, this depression becomes 

 posteriorly deeper, more defined and triangular. 



As already observed by Miss Rathbun, the 5 th abdominal somite is almost as a rule 

 bluntly and indistinctly carinate, the posterior extremity, however, is unarmed; it was previously 

 overlooked by Stimpson and by me. The 6 lh somite, hardly shorter than the 5 ,h , is regularly 

 rounded dorsally and carries at the base a broadly triangular, transverse prominence, which 

 "is convex anteriorly and which, in a lateral aspect, looks like a low subacute tubercle. The 

 posterior margin of the dorsal surface presents at either side a small narrow notch and close 



