No. 412.| MORTH-AMERICAN INVERTEBRATES. 305 
é’. Colony not branched. Hydrorhiza of anastomosing canals, form- 
ing an incrusting base, overlaid with ectodermal ccenosarc. 
c. Hydranths with sessile, fixed gonophores . HyYDRACTINIDA, 5 
c’. Hydranths producing free meduse . . . PODOCORYNID&, 6 
a’. Hypostome trumpet-shaped or hemispherical . . EUDENDRID&, 4 
ca) 
Hydranths with more than a single whorl of filiform tentacles : 
a. Stem provided with definite sheath of horny perisarc. 
b. Distal tentacles in two whorls . . . . . HYBOCODONID#, Io 
&’. Distal tentacles not in two whorls . . . . . TUBULARIDA, 9 
a’. Stem not provided with definite sheath of perisarc, more or less 
definitely marked with longitudinal flutings or ccenosarcal channels 
CORYMORPHIDA, § 
4. Hydranths with scattered, somewhat spirally disposed, capitate tentacles 
COL ORE aes oneal ae veiled yieyhy “gmt ia CORYNID&, 2 
5. Hydranths with proximal circle of filiform tentacles, and with distal 
capitate tentacles on hypostome . . .. . . . . PENNARIDE, 7 
I. CLAVIDA. 
Colonial, stems simple or branching, hydranths elongate, clavate, with 
numerous filiform tentacles irregularly disposed over the body. Gono- 
phores borne upon hydranth, or on special branches, or occasionally arising 
from the hydrorhiza. Medusoids never free. 
GENERA. 
1. CLAVA. Colony of simple, unbranched individuals, devoid of peri- 
sarc, except near the base. 
2. RHIzOGETON. Colony very similar to Clava. Gonophores arising 
from hydrorhiza. 
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 
covering, which extends slightly upon the 
bases of the polyps. Tentacles numerous, 
filiform, and scattered over the hydranth. 
Gonosome: Gonophores in clusters at base Fic. 1.— Clava leptostyla Ag. 
of tentacles, medusoids never becoming free. Cdeped ron alan) 
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 Cold Spring 
Harbor, Woods Holl, Hadley Harbor, etc. 
