10 THYROSCYPHUS. 
This is a very large, strong form, rendered striking by its regularly pin- 
nate hydrocaulus, and its large, nearly cylindrical hydrothece, with perfectly 
even orifice margined by a narrow clear band. 
Without a knowledge of the gonosome its reference to Obelia must be 
regarded as purely provisional. 
The beautiful little Zafoéa venusta crept over the stem and pinne of one 
of the specimens. 
Obelia longicyatha. 
Pl VII. Figs. 4, 5. 
Trophosome. — Hydrocaulus attaining a height of nearly an inch, fascicled 
below, alternately branched ; main stem annulated for a short distance above 
each ramulus; ramuli annulated at their origin; hydrothecal peduncles of 
moderate length, more or less annulated. Hydrothecs narrow, deep, nearly 
cylindrical above, and then tapering towards the base; the orifice cut into 
about twenty acute, deep, narrow teeth. 
Gonosome not known. 
Dredged from a depth of 90 fathoms off the Florida Reef. 
The specimens were found attached to Halecium macrocephalum. It is a 
delicate species with the hydrothece very thin and compressible. No gono- 
some was present, and its reference to Obelia is therefore only provisional. 
THYROSCYPHUS Atiman nov. gen. 
GENERIC CHARACTER. 'rophosome.— Hydrocaulus divided into internodes, 
each internode carrying a hydrotheca. Hydrothece pedunculate ; orifice 
closed by an operculum which is formed by four converging valves. 
Gonosome not known. 
The small and definite number (4) of valve-like segments composing the 
operculum of the large and strong hydrothece, combined with the very 
definite division of the hydrocaulus into distinct and equal internodes, dis- 
tinguishes the genus Thyroscyphus from the other operculate genera of the 
Campanularide. It is highly probable that if we were acquainted with 
the gonosome other and still more important characters would be found. 
