Limitation of Genera among the Hydroida. 371 
II. 
Synopsis of the Genera and Species of Campanularian Hydroids 
with known trophosomes. 
Campanularide. 
1. Campanutaria, Lamarck (in part). 
Trophosome-—Hydrocaulus simple or branching, rooted by 
a creeping filiform hydrorhiza ; hydrothece bell-shaped, with an 
entire or serrated margin, and destitute of an operculum ; tenta- 
eles surrounding the base of a large, very contractile metastome. 
Gonosome.—Gonangium seated either on the hydrorhiza or 
hydrocaulus, and containing phanerocodonic gonophores. Um- 
brella, at the time of liberation, deep bell-shaped; manubrium 
of moderate size, with the mouth provided with four shallow 
lips, or simple; radiating canals four; marginal tentacles four, 
with bulbous bases, destitute of ocelli; lithocysts eight, two in 
each interradial space, and never developed upon the base of a 
tentacle; generative elements developed in special sporosacs, 
which are borne as buds on the radiating canals. 
As the Medusa advances towards maturity, the marginal ten- 
tacles increase in number, and the oral lobes of the manubrium 
become more decided. 
The name of Campanularia was originally applied by Lamarck to 
certain Hydroids which had been a short time previously distributed. 
by Lamouroux under two generic names, Clytia and Laomedea. 
The genera Clytia and Laomedea, as defined by Lamouroux, were 
constructed on insufficient and imperfectly comprehended characters, 
and cannot stand; while, at the same time, Lamarck’s genus Cam- 
panularia involves two distinct generic types. For one of these 
types the name of Campanularia ought to be retained, while for the 
other we may choose between Clytia and Laomedea of Lamouroux. 
Laomedea, however, has been in more general use among authors, 
and it will therefore be convenient to retain it; while Clytia, which 
includes only forms referable to Campanularia or to Laomedea, must 
accordingly be suppressed. 
The Medusa of Campanularia, as this genus is here defined, is 
referable to a part of Gegenbaur’s genus Hucope. The Meduse in- 
cluded by Gegenbaur under this name belong to two distinct types, 
—one distinguished, in its mature state, by its deep bell-shaped 
umbrella, its comparatively small number of marginal tentacles, and 
the position of the lithocysts in the centre of the interval between 
two tentacula ; the other by its shallow, almost disc-shaped umbrella, 
its very numerous tentacula, with reentrant bases, and the position 
of the lithocysts—each on the inner side of the base of a tentacle. 
This latter group comprises the forms to which Péron and Lesueur 
had long ago given the name of Odelia ; while, if Hucope be retained 
as a generic appellation, it must be confined to the former. 
