HYDROIDS OF THE WOODS HOLE REGION. 
355 
CALYCELLA. 
Trophosome. — Stem a creeping rootstock parasitic on other species of hydroids, polyzoons, etc., 
sending forth short annulated pedicels bearing tubular hydrothecse with distinct, segmented opercula. 
Gonosome. — Gonangia oval, borne on the rootstock and, when mature, bearing globular acrocysts. 
Calycella syringa (Linn.). Fig. 47. 
( Sertularia syringa Linn., Syst. Nat,., p. 1311.) 
Trophosome.— Pedicels shorter than hydrothecse, very deeply annulated. Hydrothecae tubular, 
with thick horn-colored walls and slightly sinuated margins; opercular segments rather short, triangular, 
and capable of being drawn into the hydrotheca when the hydranth is retracted. There is often a sort 
of an addition or tubular extension beyond the end of the hydrotheca, with a distinct margin bearing 
the opercular segments. 
Gonosome. — Gonangia oval, borne on short annulated pedicels and, when mature, with globular 
acrocysts. 
Distribution. — Found abundantly in the Woods Hole region, growing over all sorts of plant-like 
marine organisms, especially other hydroids. 
CUSPI DELLA. 
Trophosome.- — Hydrothecse sessile with a conical operculum. Hydranths with a conical hypostome. 
Gonosome. — Not known. 
Cuspidella costata Hincks. 
(British Hydroid Zoophytes, p. 210.) 
Trophosome. — Hydrothecse perfectly cylindrical and sessile, encircled with usually three sharply 
defined annulations dividing the hydrotheca externally into four zones; operculum composed of 
numerous segments, the distal ends of which can be retracted within the hydrotheca. 
Gonosome. — U nkno wn. 
Distribution.— Reported by Professor Verrill from Fisher Island Sound, 9 to 11 fathoms. 
This species is identified with doubt by Verrill. 
LAFCEID/E (modified). 
The modification consists of the removal of the small monosiphonic species, such as Lafcea 
pocillum, which I have placed in Allman’s genus Hebella, and the genus Calycetta, which I have placed 
in the family Campanulinidw. 
Trophosor. .e. — Stem fascicled. Hydrothecse tubular, without a partial septum dividing the 
hydrothecal cavity from that of the pedicel; margin without teeth or opercula. Hydranths with a 
conical proboscis. 
Gonosome. — Gonangia found in compact masses incrusting the fascicled stem, oblong, each female 
gonangium containing a single ovum. The gonosome of Lafcea was long regarded as a distinct 
hydroid organism under the name Coppinia arcta. 1 
LAFCEA. 
This being the only genus of Lafceidse found on the New England coast, it can be identified by the 
family characters as given above. 
Key to the species of Lafcea found in the Woods Hole region. 
HydrothecEe short, almost sessile L. clumosa. 
Hydrothecse slender, with distinct pedicels which are waved or twisted L. gracillima. 
Lafcea clumosa Fleming. Fig. 48. 
(Phil. Journ., ii, p. 83.) 
Trophosome . — Stem simple, in the form of a creeping rootstock, or compound and erect. Hydro- 
thecas strong, large, tubular, with short, sometimes hardly evident, pedicels. 
1 See New Hydroids from Alaska and Puget Sound, C. C. Nutting. Proc. U. S. N. M., vol. xxi, p. 747. 
