446 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



CUMACEA. 



Diastylis quadrispinosus G. O. Sars. 



Stations 871, 873, 878 ,• 100 to 142 fathoms. 



STOMATOPODA. 



Lysiosquilla armata, sp. nov. 



This species appears to be closely allied to L. spinosa Miers, from the 

 Indian Ocean and New Zealand, or at least more closely than to any of 

 the other species contained in Mr. Miers's recent review of the Squillidse 

 (Ann. Mag. Nat. Hist., V, v, pp. 1-40, pis. 1-3, 1880). 



The carapax is smooth and abont once and two-thirds as long as the 

 breadth at the anterior margin, which is about two-thirds of the greatest 

 breadth. The rostral plate is about half as broad as the anterior part 

 of the carapax, very slightly longer than broad, the lateral edges not 

 angulated, but strongly convex in outline, and curved regularly round to 

 the short but sharp and acuminate tip. The four exposed thoracic 

 somites and the first abdominal somite increase rapidly in breadth pos- 

 teriorly, but from the second to the fifth somite the abdomen is of a 

 nearly uniform width, which is about equal to the length of the carapax. 

 The free thoracic somites, like the anterior abdominal, are smooth and 

 unarmed, except that the first somite projects downward either side in 

 a lamellar, transverse, dentiform process below the posterior margin of 

 the carapax. The five anterior abdominal somites are evenly rounded 

 above and smooth, but the posterior edge of the fourth somite is armed 

 either side for about a fourth of its length from the lateral margin with 

 slender, spiniform teeth, directed backward, and the entire i^osterior 

 margin of the fifth somite is armed in the same way. The sixth somite 

 is about three times as broad as long, only a little narrower than the 

 fifth ; the postero-lateral angle each side is armed with a stout, denti- 

 form spine, back of and within which the dorsal surface is uneven and 

 armed with five to seven spines or tubercles, of which the two or three 

 most posterior are slender spines, but the others more or less tuberculi- 

 form and inconspicuous ; the middle portion of the dorsal surface is 

 smooth, and the posterior margin, except a short space each side, is 

 armed with slender, spiniform teeth, as in the fifth somite. 



The telson is nearly as wide as the sixth abdominal somite and about 

 once and two-thirds as wide as long; the middle portion of the dorsal 

 surface rises in a smooth, oval, longitudinal area, projecting behind abave 

 the posterior margin, limited each side by a line of short spinules,.and 

 its narrow posterior extremity truncated and three-lobed or obtusely 

 tridentate ; each side of this smooth area the surface is armed with many 

 spinules or small tubercles, showing a tendency to arrangement in longi- 

 tudinal lines ; the lateral margins are expanded in front of the large 

 lateral spines of the posterior margin and armed with a few spinules ; 

 the posterior margin is armed each side with three spines, of which the 



