No.413.] MORTH-AMERICAN INVERTEBRATES. 381 
1, C. bicophora Ag. (FIG, 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. 
Meduse 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 
edusæ. Fic. 16, — Clytia bicophora Ag. 
(After Agassiz.) 
Habitat : Similar to last species. 
3, C. grayi Nutting.’ 
Trophosome : Stem simple or irregularly branched, strongly annulated 
except in middle branch. Hydrothecæ very large, cylindrical. Numerous 
marginal teeth, rounded and not deeply cut. Hydranth with about twenty 
tentacles 
Gon : Gonangia oblong, conspicuously and regularly annulated, 
attached » creping rootstocks. 
Habitat : Growing on living worm tubes, composed of sand. Dredged 
from Pt of 31 fathoms. The largest Clytia yet found in American 
waters. 
Obelia Peron and Leseur. 
Generic characters : Colony often plantdike, of whitish color, attached 
by M dsl hydrothecae campanulate and devoid of operculum. 
angia borne on stems and branches, producing free medusæ character- 
ted by numerous marginal tentacles, four radial canals, and eight otocysts 
symmetrically disposed on the inner margin of each interradial quadrant. 
1 Condensed from Professor Nutting’s original description. 
