No. 412.] MORTH-AMERICAN INVERTEBRATES. 305 
&. Colony not branched. Hydrorhiza of anastomosing canals, form- 
ing an incrusting base, overlaid with ectodermal ccenosarc. 
c. Hydranths with sessile, fixed gonophores . HYDRACTINIDA, 5 
c. Hydranths producing free meduse . . . PODOCORYNIDA, 6 
a’. Hypostome trumpet-shaped or hemispherical . . EUDENDRIDA, 4 
3. Hydranths with more than a single whorl of filiform tentacles : 
a. Stem provided with definite sheath of hdi perisarc. 
6. Distal tentacles in two whorls . . . . HYBOCODONIDA, IO 
/. Distal tentacles not in two whorls . . . TUBULARIDA, 9 
a’. Stem not provided with definite shéath of perisarc, more or less 
definitely marked with longitudinal flutings or ccenosarcal channels 
CORYMORPHID&, 8 
4. Hydranths with scattered, somewhat EUM disposed, capitate tentacles 
COR 
only ORYNIDÆ, 2 
5. CORN SR with odit AH at filiform RESI E and with distal 
capitate tentacles on hypostome . . . . . . . . PENNARIDA, 7 
I. CLAVIDA. 
Colonial, stems simple or branching, hydranths elongate, clavate, with 
numerous filiform tentacles irregularly disposed over the y. Gono- 
phores borne upon hydranth, or on special branches, or occasionally arising 
from the hydrorhiza. Medusoids never free. 
GENERA. 
I. CLAVA. Colony of simple, unbranched individuals, devoid of peri- 
2. RHIZOGETON. Colony very similar to Clava. Gonophores arising 
from hydrorhiza. x 
3. CORDYLOPHORA. Colony profusely 
branched and with definite sheath of perisarc. 
Clava leptostyla Ag. 
Trophosome: Hydranths simple, with slen- - 
der basal portion which arises from a filiform 
hydrorhiza protected by a delicate perisarcal 
filiform, and scattered over the hydrant 
Kondomi Gohachinesd in clusters at base Fic. 1. — Clava — Ag. 
of tentacles, medusoids never becoming free. VENIET tS 
Male gonads of a bright pinkish hue, similar, in general, to that of the 
colony. Female gonads of a rather distinctly purple color 
Habitat: Shallower waters on fucus, docks, sea wall, etc., at t Cold Te 
Harbor, Woods Holl, Hadley Harbor, etc. 
