430 PROCEEDINGS OF UNITKD STATES NATIONAL MUSEUM. 



at about the middle of the carapax and another a little back of the 

 anterior margin, and in front of the latter the carina is almost wholly 

 obsolete. The lateral carince are prominent along the inner sides of 

 the orbits, terminating in front in the elevated and irregularly dentate 

 inner angles of the orbits. Just back of the orbit there is a hiatus in 

 the carina, from which the carina extends uninterruptedly to near the 

 posterior margin, though its crest is minutely and obscurely dentate. 

 The surface of the longitudinal depressed spaces between the median 

 and lateral carinse are naked and nearly smooth, and so is the narrow 

 and slightly concave space between each lateral carina and the edge of 

 the carapax, excei)t for a line of small tubercles just outside the carina 

 and a few additional ones outside of these, near the postero-lateral angle. 

 The lateral margin is thin and the edge sharp, and divided by a sharp 

 incision at the cervical suture, by an incision slightly less deep a little 

 way back of the cervical suture, and by two or three obscure notches 

 along the branchial region, while the edge between these incisions and 

 notches is irregularly and very minutely dentate. 



The eyes are large, with an expanded cornea, and black. The two 

 lobes of the antennulary somite rise in front into small dentiform tuber- 

 cles, and so do the first and second of the dorsally exposed segments of 

 the antennse. The second exposed segment of the antenna is about as 

 broad as long, carinated above, acutely angular in front, and the inner 

 and outer edges are each armied with three teeth, of which the anterior 

 in each case is obscure. The terminal segment is short, and the slightly 

 arcuate anterior margin is deeply flve-lobed. 



The sternum is triangular and very broad, the breadth between the 

 bases of the posterior legs being nearly as great as the length along the 

 median line. The edges are slightly raised abov^e the bases of the legs, 

 and terminate posteriorly, back of and below the base of the fifth leg, 

 in a conspicuous spine, directed backward. 



The abdomen, to the tip of the telson, is twice as long as the carapax 

 along the median line above, is at base much narrower than the cara- 

 pax, and tapers regularly and so rapidly that at the sixth somite it is 

 little more than two-thirds as broad as at base. There is a slight median 

 carina on the second to the fifth somite, and the dorsal surface is naked 

 and sparsely punctate, but otherwise nearly smooth. The pleura of the 

 second, third, fourth, and fifth somites are nearly perpendicular and 

 slightly carinated in the middle ; the second is broader than the others 

 and nearly right-angled, but terminates in a spiniform tip, turned bacli;- 

 ward ; the third is angular, but not spiniform at the extremity; and 

 the fourth and fifth are obtuse or rounded. The sixth somite is about 

 as long as, but considerably narrower than, the fifth, and its pleura are 

 small and narrowly triangular. The telson is much longer than broad, 

 tapers very slightly distally ; the posterior portion is very thin, delicate, 

 ami transparent, and the posterior edge is slightly curved and the angles 

 rounded. The lamellce of the uropods are as long as and much broader 



