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430 PROCEEDINGS OF UNITED 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 carine 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 carinee are naked and nearly smooth, and so is the narrow 
and slightly concave space between each lateral carina and the edge of 
the carapax, except for a line of small tubercles just outside the carina 
and afew 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 antenne. 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 armed with three teeth, of which the anterior 
in each ease is obscure. The terminal segment is short, and the slightly 
arcuate anterior margin is deeply five-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 above 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 punetate, but otherwise:nearly smootb. 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 back- 
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, 
and transparent, and the posterior edge is slightly curved and the angles 
rounded. The lamelle of the uropods are as long as and much broader 
