22 THE VOYAGE OF H.M.S. CHALLENGER. 



Plumularia insignis, however, is altogether a larger and much more robust form, while 

 the hydrocladia are longer and occupy a greater length of their supporting branches, ex- 

 tending from the distal extremity of these nearly to the base. In Plumularia ahietina, 

 on die other hand, a considerable portion of the branch towards its proximal end is desti- 

 tute of hydrocladia. 



The specimen had numerous indi^^dua]s of an Avicula-like fry adhering to it, a 

 feature which has been reproduced in the dra^miug. 



Dredged off Prince Edward's Island, from a depth of 150 fathoms (?). 



Plumularia stylifera, n. sp. (PI. IV. figs. 1, 2). 



Trophosome. — Colony attaining a height of about an inch and a half, stem simple 

 monosiphonic, hydrocladia alternate, about one-tenth of an inch in length, and with the 

 hydrotheca-bearing internodes usually separated by an intervening intcrnode which does 

 not carry a hydrotheca. Hydrothecse rather large, adnate only by their base to the 

 supporting internode, flanked on each side by a long slender process, which springs from 

 the internode and carries a lateral nematophore on its summit ; a single mesial 

 nematophore borne by the hydrothecal internode at the proximal side of the hydrotheca, 

 and another liy the intervening internode. 



Gonosome. — Gonangia springing from the hydrothecal internodes at the proximal side 

 of the hydrotheca, ellipsoidal, wdth a truncated summit \\hich opens by a lid, and with a 

 pair of nematophores carried near its proximal end. 



The great length of the process which supports the lateral nematophore on each side 

 of the hydrotheca presents a striking feature. The present species, however, is not the 

 only one in which this process attains a considerable length. It is nearly as long in the 

 European Plumularia catharina and in other species closely allied to the latter, as well as 

 in Antennulana fasciculans of the present Report. 



Plumularia stylifera lias many points of affinity with Plumularia catharina, which it 

 resembles not only in the long style-like process which supports the lateral nematophore, 

 but in the presence of a pair of nematophores on the proximal end of the gonangium, and 

 in the general form of the hydrotheeae and their su^iporting pinnae. Indeed, it differs 

 from it mainly in its more delicate habit and shorter and more approximated hydrocladia, 

 which are disposed alternately on the stem instead of being opposite, as in Plumularia 

 catharina. 



Dredged off Nightingale Island, Tristan d'Acuuha, Station 135, from a depth of 

 100-150 fathoms. 



Plumularia armata, n. sp. (PI. IV. figs. 3, 4). 



Troj^hosome. — Colony attaining a height of about two inches ; stem monosiphonic 

 irregularly and sparingly branched, divided into internodes, each of which carries a hydro- 



