26 'S'. I. Smith on Brazilian Crustacea. 



Palsemon ensiculus, sp. noY. 



Plate I, figure 2. 



The carapax is somewhat gibbous, and the antennal and hepatic 

 spines are slender, sharp and of about equal size. The rostrum is 

 very long, strongly curved downward for the basal half of its length, 

 the terminal half very slender, nearly straight, but strongly inclined 

 upwards ; it is armed above with nine to twelve short teeth, which are 

 ciliated along their edges, and of which seven or eight are on the 

 basal portion, and the others near the tip, and below with eight to 

 twelve teeth. 



The eyes are large and the peduncles rather long and slender. The 

 flagella of the antennula are very long, the outer flagellum about as 

 long as the whole body and the inner a little shorter. The peduncle 

 of the antenna is armed with a small spine on the outside just below 

 the articulation of the basal scale ; the basal scale is long but not 

 reaching, by considerable, the tip of the rostrum, the extremity evenly 

 rounded and extending considerably forward of the small, acutely 

 pointed tooth at the anterior extremity of the outer margin ; the fla- 

 gellum is very long, considerably exceeding in length the flegella of 

 the antennuhx). The external maxillipeds are slender, reaching slightly 

 beyond the base of the flagella of the antennae. 



The first pair of thoracic legs are very slender, reaching slightly 

 beyond the basal scales of the antenna^, smooth and naked, except a 

 few fiiscicles of hairs on the hands. The second pair of legs in the male 

 are very long and quite slender, in full-grown specimens the merus 

 reaching beyond the tip of the antennal scale and all the segments to 

 the base of the fingers closely beset with short spinules ; the hands 

 ai-e cylindrical, not swollen, the fingers slender and sparsely clothed 

 with short, downy pubescence. In the females and young the second 

 pair of legs are considerably smaller and much less spinulose. The 

 third pair of legs reach to the tips of the basal scales of the an- 

 tenna?. The fourth and fifth pairs are successively a little longer. 



The abdomen is rather slender. The penultimate segment is long 

 and narrow, the length above being nearly or quite twice as great as 

 the breadth ; the lamelliform appendages are rather narrow, the inner 

 ones rather acutely rounded at the tips and reaching a little beyond 

 the terminal segment of the abdomen, the outer ones evenly rounded 

 at the tips and considerably longer than the inner ones. The terminal 

 segment is narrow and tapers regularly to a very slender and acute 

 point. 



