FAMILY TIES 361 



groups. The specific name refers to the serrate margin of 

 the movable branch of the uropods. Sphceroma curium, 

 Leach, is common among seaweeds on the coast of Devon, 

 but isolated rather than in groups. Spho&roma Prideaux- 

 i-anum, Leach, may be regarded as a synonym of the pre- 

 ceding, founded on large specimens. Sphceroma rugicauda, 

 Leach, is distributed over the coasts of England, Scotland, 

 and Ireland, frequently where the water is not very 

 saline, as, for instance, at Barnstaple in North Devon. 

 The stilets of the second pleopods in the male are very 

 elongate, apically widened and rounded. Sphceroma 

 Hookeri, Leach, is very similar to the preceding species, 

 but distinguished by two small longitudinal ridges 011 the 

 pleon. Both species have been taken in company on the 

 coast of Sussex. 



Zuzara, Leach, 1818, was established for species differ- 

 ing from Sphceroma by having the outer branch of the 

 uropods larger than the fixed inner one, and concave above 

 instead of flat. The species also have the sixth segment 

 of the peraeon dorsally produced. 



Ncesa, Leach, 1818 (Nesce-a, Leach, 1814, preoccupied), 

 has the sixth segment of the peraeon larger than the others, 

 and produced backwards in a bidentate process. The uro- 

 pods are affixed not at the base, but near the further end, 

 of the terminal segment, and, while the fixed inner branch 

 is directed transversely inward, the movable outer one ex- 

 tends backwards beyond the end of the segment. In the 

 British species Ncesabidenlata (Adams), the pleon is rugose 

 with two dorsal tubercles and a terminal excavation. Bate 

 and Westwood suggest that this species may prove to be 

 the male of Dynamene Montagui, Leach, in which there 

 are two dorsal tubercles on the sixth segment of the peraeon. 

 and two on the pleon. It seems not improbable that the 

 species named Dynamene rubra and Dynamene viridis by 

 Leach, and Campecopea versicolor by Rathke, may repre- 

 sent the female, and Dynamene Montagui the young male, 

 of Ncesa bidentata. These forms are all found on British 

 coasts under similar conditions and with the same varia- 

 tions of colour green, or red, or variously mottled ; but 



