356 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Gonosome. — Gonangia in masses, incrusting the fascicled stem, so closely crowded as to be pressed 
together, tubular or oblong oval with short bottle-shaped necks. Both sexes found in the same colony. 
Distribution. — Found growing on other hvdroids on Nantucket Shoals. (VerrilO 
Lafoea gracillima (Alder). Fig. 49. 
(Campanularia graciUima, Cat. Zooph. Northumb. and Durham, p.39.) 
Trophosome. — Stem erect, fascicled, often irregularly branched. Pedicels slender, sinuous or 
apparently twisted. Hydrothecse very slender, delicate in texture, often slightly curved. 
Gonosome. — Much like that of L. dumosa, and heretofore known as Coppinia arcta. 
Distribution. — Reported from the New England coast by Professor Verrill. Although not 
specifically reported from the Woods Hole region, it doubtless occurs there, as its distribution is much 
like that of L. dumosa. 
HALECIDiE. 
Trophosome. — Hydrothgcte alternate, reduced to the form of saucer-shaped hydropliores, usually 
borne on tubular pedicels; margins even, often reduplicated several times, and surrounded by a circlet 
of bright, bead-like dots. Hydranths large, with conical proboscis, not capable of retracting within 
the hydropliores. 
Gonosome. — Gonangia producing planuhe, and usually different in the two sexes, that of the 
female often being surmounted by a pair of hydranths. 
HALECIUM. 
The single genus can lie identified by the characters given above. 
Key to species of Halecium found in the Woods Hole region. 
A. Hydrophores borne on distinct pedicels. 
a. Stem fascicled. 
b. Colony flabellate in form; aperture of female gonangium terminal, but not central. Pedicels 
short ..II. halceinum. 
b'. Colony dendritic in form. Female gonangia with round lateral apertures. Pedicels short II. beani. 
b". Colony with slender branches. Female gonangia as in II. halecinum, but with end emarginate II. gracile. 
a'. Stem not fascicled, irregularly branched, annulated II. tenellum. 
A'. Hydrophores sessile, borne directly on broadened shoulder of internodes of stem II. articulosum. 
