PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 449 



the first segment of the peduucle is nearly as long as the widtli of the 

 head; the second segment is much more slender than the first and more 

 than three times as long ; the third segment is more slender than the 

 second and cousiderabl}' longer than tlie first ; there is a well-developed 

 secondary flagellum, as long as the third segment and composed of 

 about nine slender segments; the primary flagellum is very slender 

 and about one and a half times as long as the peduncle. The third 

 segment of the pedun(;le of the antenna just reaches tlie distal end of 

 the first segment of the peduncle of the antennula; there is a small, 

 spiuiform tubercle on the outside of the first segment, in line with the 

 lateral spine of the head and the spiniform anterior angles of the first 

 and second epiraera. The distal portion of each antenna is wanting in 

 the single specimen examined. 



The first gnathopods are of nearly the same form as in iV. monstrosa, 

 as figureil by Boeck, but the inferior edge of the propodus is nearly 

 straight, and the spine at the distal end is directed straight out in line 

 with the edge, and not downward as in the figure ot N. monstrosa. In 

 the second pair of gnathopods the carpus is about twice as long as 

 broad, and has the unarmed i^rehensile edge much less oblique than 

 represented in the figure of iV. monstrosa. The first three pairs of i)er- 

 ieopods are very nearly as in N'. monstrosa ; the last two pairs are want- 

 ing in the specimen. 



The pleon is nearly as high but very much narrower than the last so- 

 mites of the perreon : the first three somites are subequal in size and 

 very similar in form; the fourth is as long but not quite as high as 

 the third ; the fifth is not more than two-thirds as long as the fourth ; 

 the sixth is only about half as long as the fifth. The telson is partially 

 consolidated with the sixth somite, and somewhat triangular, with an 

 obtuse lip. The uropods are as in N. monstrosa. 



Measurements. 



mm. 



Length from front of head to tip of telson 25. 



Length of head and peraeou 17. 8 



Length of antennula 35. 



Length of lirst segment of peduncle 2. 4 



Length of second segment S.2 



Length of third segment ,*?. 2 



Length of secondary flagellum 3. 2 



Length of carpus in first gnathopod 3. 1 



Breadth of same 1. 8 



Length of propodus of first gnathopod 2. 5 



Breadth of same 2. 



Lengi h of dactyl us 2. 7 



Length of carpus of second gnathopod 2. 7 



Breadth of same 1.4 



Length of propodus of second gnathopod 2. 5 



Breadth of same 1.8 



Length of dactylns 2. 



Proc. Nat. Mus. SO 29 Jan. 31, 1881. 



