578 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 88 



Gonosome (not previously described). — Gonangium arising from 

 the stolon with a pedicel similar to that of the hydrotheca, similar 

 in shape but much larger and somewhat curved ; distal end obliquely 

 truncate, narrowed but slightly: sporosacs few, similar in appear- 

 ance to those in the genus Gonothyraea. 



Type—U. S. N. M. No. 43437. Taken by the United States Fish- 

 eries steamer Fish Hawk off Marthas Vineyard, latitude 40°03' N., 

 longitude 70°31' W., growing over a Halecium in 100 fathoms, Au- 

 gust 23, 1881. 



Genus HALECIUM Oken 



HALECIUM DIMINUTIVUM, new species 

 < 



Plate 33, Figure 6 



Trophosome. — Colony minute from a creeping stolon, with no 

 continuous main stem; a simple pedicel grows from the stolon, giv- 

 ing rise to a flaring hydrophore, terminally; in some cases, just 

 below the hydrophore, a second pedicel may be given off, turning 

 upward abruptly at the base; in one instance this is repeated so 

 that there are three hydrophores in the colony; this colony had a 

 total length of 1.2 mm. The stolon is not annulated, but the pedicels 

 are decidedly so; the interspace extends outward to a decided ridge 

 so that the surface of the pedicel is much more irregular than in 

 ordinary annulated pedicels or stems. 



Gonosome. — Unknown. 



Type.—US.'^M. No. 43438. Taken by the United States Bureau 

 of Fisheries on Nantucket shoals, on Sertularella.^ depth not given. 



EUPERISIPHONIA, new genus 



Trophosome. — Colony with a stout, rigid stem and somewhat 

 slenderer, but still rigid, branches. Stem and branches fascicled, the 

 fascicle consisting of an axial tube, bearing hydrothecae, and sev- 

 eral peripheral tubes that are nonthecate. The hydrothecae are reg- 

 ularly alternate, loosely adherent for a portion of their length. On 

 the main portion of the axial tube there are no nematophores, but 

 one is present at the base of each hydrotheca. The peripheral tubes 

 are provided with numerous long, slender nematophores. 



The trophosome of this species resembles that of Perisiphonia but 

 differs from it in having adherent hydrothecae and nematophores 

 at the base of the hydrothecae. 



Gonosome. — Unlaiown. 



Genotype. — E. rigida, new species. 



