THE CAMPANULAHID^ AND THE BONNEVIELLID^. 53 



annulated throughout. Under each hydrotheca is a distinct globular annulation. Both the pedicel wall and that 

 of the hydrorhiza are strongly thickened. Hydrothecse campanulate, .34 to .40 mm. long and .2 mm. in diameter at 

 the margin. Hydro thecal walls very strongly and evenly thickened except on the distal portion which is thin-walled 

 and ornamented with 10 well developed teeth. At the base of the hydrotheca the thickened wall forms a more or less 

 well developed diaphragm. Hydranth small, entirely retracted within the small hydrothecee. 



Gonangia borne on the hydrorhiza and distinguished for their proportionally large size, their even surface and 

 their remarkably thickened walls. Length about 1 mm. and width .5 mm. They gradually diminish in size toward 

 the base where they pass into a short pedicel. Their distal ends are truncated and have a moderately high collar 

 around the opening. 



Distribution. — The type-locality is Lennox Island, Patagonia, 12 to 28 fathoms (Jader- 

 holm). 



Genus CLYTIA Lamouroux (modified by Hincks). 



Clytia Lamouroux, Histoire des Polypiers Coralligfenes Flexibles, 1816, p. 200. 

 Campanularia (part) Lamarck, Hist. Nat. Anim. sans Vert., vol. 2, 1836, p. 129. 



The original definition for this genus is as follows : 

 Polypier phytoide, rameux, filiforme, volubile ou grampant; cellules campanulees, pedicelees; pedicelles longs 

 ordinairement contourn^s. 



Agassiz 1 revives this name and appHes it to the section of the Lamarckian genus Campanu- 

 laria to which Campanularia johnstoni Hincks belongs. He does not, however, define the 

 genus. 



Hincks ^ was the first to give a satisfactory definition to this genus, the main distinction 

 being found in the gonosome, the gonangia producing medusas with four radial canals, four 

 marginal tentacles and eight lithocysts. It is only by this means that the genus can be differ- 

 entiated from Campanularia, Ohelia, Oonoihyrsea, etc. 



A definition which wiU serve the present purpose may be stated as follows : 



Trophosome. — Colony often simple but always consisting of a creeping rootstock from 

 which spring pedicels which are not regularly branched as a rule. Hydrothecse campanulate, 

 hydranths witL trumpet-shaped proboscis. 



Gonosome. — Gonangia producing bell-shaped or hemispherical medusae which have a 

 small manubrium, 4 tentacles at liberation, and 8 hthocysts. 



KEY TO THE SPECIES OF CLYTIA FOUND IN AMERICAN WATERS. 



Colony consisting of stems bearing branches or pedicels. 



Margin smooth .; hakeri. 



Margin toothed. 



Marginal teeth keeled and pedicels short hendersoni. 



Marginal teeth not keeled. 



Pedicels bent upward at base, long. 



Gonangia not annulated, hydrothecae deeply campanulate atlenuata. 



Gonongia annulated, hydrothecEe not deeply campanulate, small minuta. 



Pedicels not abruptly bent upward at base. 

 Pedicels long, smooth in median part. 



Stem simple edwardsi. 



Stem fascicled below longieyatha. 



Pedicels extensively annulated. 



Pedicels given off from all sides of stem universitatis. 



Pedicels alternate, one to each intemode .fragilis. 



Colony consisting of usually unbranched pedicels springing from a rootstock. 

 Hydrothecae typically campanulate. 



Distal part of hydrothecae very thin and collapsible sargassicola. 



Distal part of hydrothecse not thin and collapsible. 



Pedicels short, gonangia flask-shaped noliformis. 



Pedicels long, gonangia cylindrical, deeply and regularly annulated. 



Diaphragm complex johnstoni. 



Diaphragm simple bicophora. 



Hydrothecas cylindrical cylindrica. 



1 Cont. to Nat. Hist. U. S., vol. 4, 1862, p. 354. 

 ' British Hydroid Zoophytes, 1868, p. 140. 



