No. 413.] MWORTH-AMERICAN INVERTEBRATES. 381 
1, C. bwophora Ag. (Fic. 16). 
Trophosome : Colony rarely attaining a height of more than an inch, 
composed of simple or sparingly branched stems. Hydrothece deeply bell- 
shaped and numerously and sharply toothed, 
borne on elongate pedicels which have terminal 
annulations. 
Gonosome: Gonangia symmetrically annu- 
lated and usually arising from the hydrorhiza. 
Medusz when first liberated of hemispherical 
shape and with four tentacles and eight otocysts. 
Habitat : Usually on fucus, occasionally on 
shells or other hydroids. 
2, C. cylindrica Ag. 
(Cont. Nat. Hist. U. S., vol. iv.) 
Trophosome : Stems simple, hydrothece tubu- 
lar, small, deep, with sharply pointed teeth. Pedi- 
cels short, with proximal and distal annulations. 
Gonosome : Gonangia oblong, somewhat flat- 
tened, devoid of annulation, producing free 
meduse. Fic. 16.— Clytia bicophora Ag. 
(After Agassiz.) 
Habitat : Similar to last species. 
3, €. grayt Nutting. 
Trophosome : Stem simple or irregularly branched, strongly annulated 
except in middle branch. Hydrothece very large, cylindrical. Numerous 
marginal teeth, rounded and not deeply cut. Hydranth with about twenty 
tentacles. 
Gonosome : Gonangia oblong, conspicuously and regularly annulated, 
attached to creeping rootstocks. 
Habitat : Growing on living worm tubes, composed of sand. Dredged 
from depth of 3t fathoms. The largest Clytia yet found in American 
waters. 
Obelia Peron and Leseur. 
Generic characters : Colony often plant-like, of whitish color, attached 
by creeping hydrorhiza ; hydrothecee campanulate and devoid of operculum. 
Gonangia borne on stems and branches, producing free medusz character- 
ized by numerous marginal tentacles, four radial canals, and eight otocysts 
symmetrically disposed on the inner margin of each interradial quadrant. 
' Condensed from Professor Nutting’s original description. 
