No. 413.]| MORTH-AMERICAN INVERTEBRATES. 383 
5, O. gelatinosa Pallas. 
Trophosome: Stems fascicled, rising from a fibrous hydrorhiza to a 
height of eight to ten inches. Branches opposite in pairs, which alternate 
with each other in vertical arrange- 
ment, presenting a verticillate appear- 
ance. Hydrothece small, borne on 
long slender, ringed pedicels, and hav- 
ing notched margins of a somewhat 
castellated form. 
Gonosome : Gonangia axillary, ovate, 
flattened at distal end and provided with 
raised orifice. Medusz with sixteen 
tentacles when liberated from gonan- 
gium. 
6, O. longissima. 
7, O. bicuspidata. Be oe 
8, O. bidentata. Fic. 18.— Obelia geniculata Linn. a, go- 
F ’ nangium of same enlarged. 
Species 6, 7, 8 are listed from Pro- 
fessor Nutting’s records, but have not been taken by the present writer. 
Campanularia Lamx. (in part). 
The generic characters are fairly explicit under the synopsis of genera. 
1, C. caliculata Hincks. 
(Clytia poterium Ag.) 
Trophosome : Stem simple, of variable length, bearing a single hydro- 
theca which is campanulate, with entire margin, and with a thick wall form- 
ing a sort of diaphragm within the lower part, thus giving the appearance 
of a double-walled cup. 
Gonosome: Gonangia irregular, oval in shape, with undulating outline 
and with wide circular aperture. Medusoids extremely degenerate. Larve 
escaping as free-swimming planule. 
Habitat : Massachusetts Bay, Nahant, Nova Scotia, on seaweed, etc. 
2, C. hincksi Alder. 
Trophosome: Stems rather long, mostly simple; hydrothece large, 
deep, almost tubular, the margins scalloped with castellated teeth. 
Gonosome: Gonangia ovate, elongate, somewhat narrowed toward ex- 
tremity, irregularly annulated throughout, borne on short, smooth pedicels. 
Medusoids degenerate; ova forming a central mass within the capsule. 
