A NEW GENUS, N/ESICOPEA 8C3 



should have been so little examined, that their relation- 

 ships are left rather to speculative argument than to any 

 basis of observed facts. I can, however, myself testify that 

 Sphceroma rugicauda, Leach, need not have recourse to 

 Cymodoce for a male form. In the character of the pleo- 

 pods Cymodoce agrees with Sphctroma as opposed to Ncesa, 

 although, as to the stilets of the second pair, in Cymodoce 

 iruncata they are apically narrowed. 



The species, Cymodoce abyssorwm^ Beddard, from 1,070 

 fathoms, off New Guinea, must be transferred to a new 

 genus, for which I propose the name Ncesicopea. The last 

 segment of the per^eon is much narrower than the segment 

 before or the segment behind it, and has the side-plates 

 rudimentary. There are two median dorsal teeth, one 

 behind the other, on the pleon. The fourth and fifth 

 pleopods have both branches fully branchial. The uropods 

 in the male have the inner branch rudimentary, the outer 

 greatly prolonged. In the female they are placed higher 

 up than in the male, with a longer inner branch, and the 

 outer not much longer than the inner. The name refers 

 to the combination of characters found in Ncesa and in the 

 genus next to be mentioned. 



Campecopea, Leach. 1811, has the sixth segmeut of the 

 pergeon produced m the male, but not in the female. The 

 uropods are inserted high up on the terminal segment, 

 and have the movable branch, long, curved, and produced 

 beyond the apex of the segment; while the inner branch, 

 marked off by a partial suture from the peduncle, is a 

 mere knob, only distinguishable on the under side. It 

 can scarcely be doubted that only one British species of 

 this genus is at present known, Cam.pecopea hirsiita (Mon- 

 tagu), of which Campecopea Cranchii, Leach, is the female. 

 The two forms are constantly found in company in the 

 little blacldsh or dark green sea-weed, LicJiina piygmcea. 

 In colour they entirely agree, as in almost all other par- 

 ticulars except the long tooth on the sixth perseon- segment. 

 In some specimens this tooth may be seen in various 

 stages of growth, while others are entirely without it. 

 All specimens roll themselves up very tightly, so that, in 



