16 HALECIUM MACROCEPHALUM. 
Just within the everted margin of the hydrophore is the circle of minute 
brilliant points which is scarcely ever absent in any species of Halecium, 
Halecium capillare. 
Thoa capillaris PourraLrs. Bull. M. C. Z., I. No. 6. 
Pl. XI. Figs. 5, 6. 
Trophosome. — Hydrocaulus attains a height of about an inch and a half, 
slender, irregularly branched, fascicled at the origin of the main stem and 
principal branches; internodes rather long. Hydrophores short, nearly 
cylindrical. 
Gonosome not known. 
Dredged five miles 8. 8. W. of Sand Key from a depth of from 90 to 100 fathoms. 
This is a small and delicate species. The circle of brilliant points which 
in almost every species of Halecium occurs just within the margin of the 
hydrophore is not here obvious. 
This is one of the specimens examined by Mr. de Pourtales, who has 
assigned to it the specific name here adopted. 
Halecium macrocephalum. 
Pl. XID. Figs. 1-5. 
Trophosome. — Hydrocaulus attaining a height of about two inches, rigid, 
stout, and very irregularly branched in all directions; main stem and 
principal branches fascicled, becoming monosiphonic distally; internodes of 
moderate length. Hydrophores suppressed. Hydranths very large, sup- 
ported directly on the fixed lateral processes of the stem. 
Gonosome. — Gonangia springing from the sides of the lateral processes 
which support the hydranths; female slipper-shaped, with the orifice situ- 
ated near the middle of one side; male smaller than female, cylindrical, 
with truncated summit. 
Dredged off Sand Key from a depth of 120 fathoms. 
Halecium macrocephalum is remarkable for the suppression of the hydro- 
phore, whose sole representative is found in the narrow membranous lip, 
which is here quite sessile on the fixed bracket-like process of the stem. 
In some of the specimens the form of the hydranths was well retained. 
These were very large, reaching when fully extended the height of about 
two internodes of the stem. 
