HALECIUM FILICULA. 15 
Lafoéina and Oplorhiza afford the only known instances in which organs 
resembling true nematophores occur outside of the family of the Plumularide. 
Oplorhiza parvula. 
Pi. VIL, Bigs. 1=3. 
Trophosome. — Hydrosoma very minute, scarcely attaining a line in height. 
Hydrothece deep, narrowing towards the summit and towards the base; 
peduncles with about two rings just below the hydrotheca, and several less 
distinct ones at their origin from the hydrorhiza. Hydrorhizal appendages 
very minute, clavate, scattered over the upper side of the hydrorhiza. 
Gonosome not known. 
Dredged south of Marquesas from a depth of 296 fathoms. 
Famity HALECIDA. 
Genus HALECIUM OKEn. 
Halecium filicula. 
v2 eXele Figs. ii —4= 
Trophosome. — Hydrocaulus attaining a height of about three inches, alter- 
nately branched; branches pinnately disposed; internodes rather long; main 
stem and principal branches fascicled, but becoming monosiphonic toward 
their distal ends. Hydrophores* with one or more usually oblique and 
irregular annulations at their base, then gradually widening from the most 
distal annulation to the summit, where they terminate in a circular and 
abruptly everted margin. 
Gonosome not known. 
Dredged south of Marquesas from a depth of 140 fathoms. 
This species is rendered striking by the graceful trumpet-shaped form of 
its hydrophores. Many of these are provided with a double or even triple 
margin, caused by the hydranth in its growth leaving behind it the old 
dilated extremity of the hydrophore, and becoming encircled by a new one, 
—acommon occurrence among the various species of Halecium. 
* The genus Halecium is destitute of true hydrothece, and the term hydrophore is here used for 
the appendages of the stem which take the place of the hydrothece in giving support to the hydranths. 
