291 PLUMULAIUID^E. 



Dorset, on Halidrys siliquosa; Teignmouth (T. H.) : near 

 lloundstonc, Gahvay (M'Calla) : profusely investing 

 about 6 inches of the stem of a Laminaria diyitata, 

 Youghal (Miss M. Ball). Miss Ball's remarkable speci- 

 men has supplied the principal cabinets in the country. 



Genus PLUMULARIA, Lamarck (in part). 



Der. Plumula, a little feather. 



AGLAOPHENIA, Lamouroux (in part). 

 PLUMULARIA, M'Crady. 

 HAHCORNARIA, Busk, MS. 



GENERIC CHARACTER. Zoophyte consisting of plumous 

 shoots, simple or branched, jointed, attached by a creeping 

 stolon; hydrotheca cup-shaped; nematophores distributed 

 alone/ the stem and branches ; gonotheca scattered or 

 crowded together, but always unenclosed, differing in the 

 two sexes. 



THE members of this genus are generally distinguished 

 by great delicacy of habit, and want the dense cor- 

 neous texture of the Aglaophenice. The nematophores, 

 which present two or three distinct forms, are usually de- 

 veloped in great profusion, and have no special connexion 

 with the calycles. 



In some of the species the gonothecse are massed to- 

 gether in great numbers, in others they are distributed 

 singly ; but they are never gathered together in companies 

 under the protection of a corbula. They differ more or 

 less in the two sexes. The polypites are commonly shaped 

 like a dumb-bell, and of very large size in proportion to 

 the calycle, into which they are not wholly retractile. 



