NEMATOBRACHION FLEXIPES. 271 



second segments a little angular or conspicuously angular above in the middle 

 line (fig. 5g). 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 simple in the male and 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. 5h-5m) differ from those in N. boopi.'^ by the 

 shape of the terminal and the proximal processes. The terminal process is 

 somewhat less thickened at the base, tapering to the narrow middle and then 

 flattened and almost abruptly and strongly expanded on the outer side and 

 feebly expanded on the iimer side; the distal half is, seen from behind (fig. 5i), 

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

 the outer proximal angle very broadly rounded and the vertex 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. 5k). The proximal process is somewhat broader than in A'^. boopis and 

 more evenly curved, its distal half is somewhat depressed, and thus broader 

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

 forming, seen from the base of the organ, an oblong-oval plate (fig. 5m) with 

 nearly the whole margin finely serrate. The median lobe long and slender 

 (fig. 5h) 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 from N. boopis, 

 but it would be a mistake to establish 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 even in less than half-grown specimens the carapace 

 has no vestige of any tooth on the lateral margins. 



Distribution. — This species was estabhshed 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° 

 10' W., and Lat. 24° 3' N., long. 25° 0' W. It is unknown from the Indian 

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

 common in the major part of the area explored in 1904-5 in the East Pacific, 

 viz. between Lat. 9° 45' N., and Lat. 25° 27' S. Ortmann has recorded it from 

 two Stations in the same area, viz. off Panama at Lat. 0° 21' N., and at Lat. 

 0° 36' N., long. 82° 45' W. The specimens in the Copenhagen Museum were 



