HYDEOIDS OF THE WOODS HOLE EEGION. 
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PERIGONIMUS. 
Trophosome. — Colony attaining a height of about 1 inch, either branched or simple; perisarc of a 
jelly-like consistency and reaching to the bases of the tentacles. Hydranth body terete, the proboscis 
being large and conical. 
Gonosome. — Gonophores borne on the branches or hydranth bodies, in our species. Medusae bell- 
shaped, with a simple or lobed proboscis. Marginal tentacles 2 or 4, not. in clusters, and with bulbous 
bases and no eye-spots. 
Perigonimus jonesii Osborn & Hargitt- Fig. 6. 
(American Naturalist, vol. xxvm, p. 27.) 
Trophosome. — Colony attaining a height of about one-fourth inch, freely branching, the branches 
erect and continuing insensibly into the hydranth body; gelatinous perisarc very thick and often 
wrinkled, reaching to the bases of the tentacles and sometimes appearing to include the proximal 
part of the latter. Hydranths with about 10 tentacles held rigidly, lint alternately depressed and 
elevated; proboscis dome-shaped or subconical. 
Gonosome. — Gonophores borne on the hydranth body or branches. Medusae ovoid, with 2 
tentacles, 4 radial canals, and 4 eye-spots; manubrium short with a 4-lobed mouth. 
Color. — Colony flesh-colored. 
Distribution. — Found on the abdomen and walking legs of Lcibinia emarginata. Collected at 
Coldspring Harbor, Long Island. 
This species does not come strictly within the Woods Hole region, but as it is the only American 
Perigonimus yet described it seemed desirable to include it here. 
Trophosome. — Colony branching, often profusely; perisarc evident, often regularly annulated. 
Hydranths with a single verticil of filiform tentacles, and a proboscis that is at times trumpet-shaped 
and at times hemispherical, the distal end being the larger. 
Gonosome. — Gonophores (male) forming verticils just beneath the tentacles of the hydranth, each 
verticil being composed of a number of gonophores radiating like the spokes of a wheel, each gono- 
phore having 2 to 4 chambers in linear series; female gonophores not in regular verticils and usually 
clustered around the hydranth bodies. No medusae. 
