2 Journal of Entomology and Zoology 
CC. Hydrotheca in a single row on stem. 
D. Hydrocladia on erect stems. 
EK. One or more intermediate internodes. Hydro- 
theca as deep as long. 
Plumularia setacea. 
EE. Septal ridges moderate, usually two in each in- 
ternode. 
Plumularia lagenifera. 
DD. Hydrocladia modified as corbulae protecting gono- 
theca. 
EK. Median tooth straight. Nine teeth. 
Aglaophenia pluma 
EE. Eleven teeth, irregular. 
Aglaophenia struthionides 
BB. Hydrotheca stalked, bell-shaped. 
C. Gonophores are sporosacs. 
CC. Gonophores are medusae. 
Campanularia exigua. 
D. Pedicels in pairs. 
Obelia gracilis. 
DD. Pedicels not in pairs. 
EK. Pedicels on shoulders produced from stem. 
Obelia geniculata. 
EF. Pedicels not geniculated, branching on all 
- sides. 
Obelia commissuralis. 
Sertularia desmoides Torrey and EHudendrium ramosum L. 
obtained during the summer of 192! are not included in this key. 
They were determined for us by Mr. W. S. Wallace of the Hopkins 
Marine Station, Pacific Grove, Calif. 
TUBULARIAE 
CORYNIDAE: No basal whorl] of tentacles, but with tentacles 
scattered irregularly over the hydranth. Tentacles knobbed. Hy- 
droid branched. 
Syncoryne mirabilis (Ag.) Torrey. U. C. pub. Zool. Vol. 1. 
1902. p. 31. 
Hydranth cylindrical. Proboscis conical. Scattering, capitate 
tentacles. Small. Bathymetrical range; exposed to breakers of 
open sea or in quiet harbours, ours on exposed pier with O. com- 
