368 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
hydrotheca, the next with one on its proximal half, and the rest of the hydrocladium being made up 
of alternating hydrothecate and intermediate internodes. Hydrothecae cup-shaped, margin entire. 
Nematophores trumpet-shaped, a pair near the top of each hydrotheca, one below its base in front, 
two on each intermediate internode, and others on the stem. 
Gonosome. — Gonangia borne on bases of hydrocladia, ovoid, deep, with subterminal aperture. 
Distribution. — Off Gay Head, 18$ fathoms. Newport Harbor; Woods Hole; off Block Island. 
(George Gray.) 
Antennularia americana Nutting. Fig. 73. 
(Monograph of American Hydroids, part 1, The PlumuiaridEe, p. 69.) 
Trophosome. — Colony composed of slender, erect stems bearing hydrocladia usually in whorls of 4. 
Proximal hydro theca on each hydrocladium borne on a long process from the stem, there being no node 
between it and the stem. Otherwise the arrangement of the internodes, hydrothecse, and nemato- 
phores are as in the preceding species. 
Gonosome. — Gonangia oblong-ovate, with a subterminal lunate aperture. 
Distribution. — Off Marthas Vineyard, Albatross. Waters of Rhode Island (specimen from Dr. 
H. C. Bumpus). 
This species, although greatly resembling .1. antennina, differs constantly in the characters given. 
In some cases, where a hydrocladium has been broken off and regenerated, there will be a node below 
the proximal hydrotheca. Otherwise the character is constant. 
Antennularia rugosa Nutting. Fig. 74. 
(Monograph of American Hydroids, part 1, The Plumularidse, p. 70.) 
Trophosome. — Colony consisting of upright stems which give off hydrocladia in whorls of 6 
or 8, no node between the proximal hydrotheca on each hydrocladium and the stem. Hydrocladia 
supported by a remarkable thickening of the perisarc on the lower side of the proximal portion of 
each. Nodes very distant and irregular, but the interiors of the hydrocladia have numerous annular 
thickenings of the periderm that somewhat resemble nodes. Hydrothecse deeper than in the other 
species. A pair of nematophores inserted on a level with top of the liydrotheca, and others scattered 
along the fronts of the internodes and around the stem. 
Gonosome. — Not known. 
Distribution. — Off Marthas Vineyard, 46 fathoms. ( Albatross . ) 
CLADOCARPUS. 
Trophosome. — Colony branched. Hydrocladia not forked. 
Nematophores neither movable nor trumpet-shaped. 
Gonosome. — Gonangia borne on the stem and protected by 
special branchlets which spring from near the bases of the hydro- 
cladia and bear nematophores but no hydrothecse. 
Cladocarpus flexilis Verrill. Fig. 75. 
(Report Com. Fish and Fisheries. 1883, p. 517.) 
Trophosome. — Stem not fascicled, long and slender; hydro- 
cladia pinnately arranged, alternate, not forked, divided into 
internodes, each of which bears an hydrotheca and has its cavity 
divided by internal ridges. Hydrothecse deep, subcylindrical, 
aperture horizontal, with a single strong anterior tooth and a 
number of shallow lateral teeth or sinuations. Nematophores 
tubular, a pair slightly overtopping the hydrothecal margin, and 
a single one below each hydrotheca, its end not rising much 
above the level of the bottom of the latter. 
Gonosome. — Gonangia growing on front of stem, protected by special branches borne on the bases 
of hydrocladia and branched like deers’ horns, each branch bearing a row of nematophores. 
Distribution. — Found in moderately deep water at various points along the Atlantic coast. 
75. Cladocarpus flexilis Verrill. 
A. Gonangia with protective branchlets. 
