NEMATOBRACHIOX FLEXIPES. 271 



second segments a little angular or consjiicuou.'^ly angular above in the middle 

 line (fig. og). The lateral plates of second to fifth segments with the postero- 

 lateral angle acute, and the plate of fifth segment besides somewhat produced 

 (fig. 5g). Preanal spine simjile in the male anil with an accessory tooth in the 

 female. — Uropods about as long as the telson ; the exopod slightly or scarcely 

 longer than the endopod. — The telson with two pairs of small dorsal spines. 



The copulatory organs (figs. 51i-5m) difl'er from tliose in A". Ixxipi.s by the 

 shape of the terminal and the proximal processes. The terminal ]irocess is 

 somewhat less thickened at the base, tai)ering to the narrow miiklle and then 

 flattened and almost al)ruptly and strongly expanded on tlie outer side and 

 feebly expanded on the inner side; the distal half is, seen from behind (fig. 5ij, 

 shaped nearly as an oblique triangle with the inner margin somewhat sinuate, 

 the outer proximal angle very broadly rounded and the \-ertex narrowly rounded; 

 a little from the distal end the posterior side shows a peculiarly raised part, the 

 shape of which is better understood when looked at from the outer side (p-. 

 on fig. .jk). The proximal process is somewhat broader than in X. baopis and 

 moi-e e\'enly cur\'ed, its distal half is somewiiat depressed, and thus broader 

 than deep; the terminal part is much flattened and considerably expanded, 

 forming, seen from the base of the organ, an (jblong-oval plate (fig. om) with 

 nearly the whole mai-gin finely serrate. The median lobe long and slender 

 (fig. oh) with its two processes nearly as in N. boopis; the two remaining lobes 

 nearly as in that species. 



Length of a large male 21.5 mm., of a female 22.5 mm. 



Remarks. — N. flexipes differs in general aspect much frcim X. boopis, 

 but it would I)e a mistake to estabhsh a new genus for its reception, because both 

 species agree with each other in all characters of real generic value. It may 

 be mentioned here that e\-en in less than half-grown si)ecimens the carapace 

 has no vestige of any tooth on the lateral margins. 



Distribution. — This species was established on two specimens from the 

 Southern equatorial current in the Atlantic. The Copenhagen Museum possesses 

 specimens from two places in the North Atlantic, viz. Lat. 31° 30' N., long. 21° 

 16' W., and Lat. 24° 3' N., long. 2.3° 0' \V. It is unknown from tiic Indian 

 Ocean and the Western Pacific, but according to the long list of Stations it is 

 common in the major i)art of the area explored in 1904-5 in tlic Ivist Pacific, 

 viz. between Lat. 9° 45' N., and bat. 25° 27' S. Ortniann has recnrded it from 

 two Stations in the same area, \iz. off Panama at Lai. fi 21' X., and a1 Lat. 

 0° 3G' N., long. 82° 45' W. The specimens in the Copenliagen Museum were 



