356 CLADONEMID^. 



CLJBONEMIDzE. 



TROPHOSOME. — Htdrocaulus developed, invested by a peeisaec. Hydkanths 

 with two kinds of tentacles, one filiform, the other capitate. 



GONOSOME. — GoNOPnoEES phanerocodonic with the radiating canals, more than 

 four, and with the marq-inal tentacles ramified. 



CLADONEMA, DnjanUn. 



Name. — From k\ucoq, a branch, aud vnm, a thread ; so named from the l)ranching tentacles 

 of the planoblast. 



Cladonema (planoblost), Stauridie (trophosome), — Biijardin. 



TROPHOSOME. — HYDEOPnYTON consisting of a branching or simple hydeocaultjs 

 arising from a creeping filiform hydeoehiza, the whole invested with a cliitinous 

 PEEisAEC. Hydeanths clavate with two verticils of tentacles, each verticil consisting 

 of four tentacles disposed in a cross, — the tentacles of the proximal verticil filiform, 

 those of the distal verticil capitate, 



GONOSOME. — Planoblasts developed from the body of the hydranth. Mature 

 PLANOBLAST with a deep bell-shaped umbrella ; manubrium with the mouth surrounded 

 by five lips ; radiating canals, eight or ten, eacli continued at the umbrella-margin 

 into a tentacle with a bulbous base which carries an ocellus ; branches of tentacles of 

 two kinds, one kind very extensile and destitute of suctorial organs, the other situated 

 at the proximal side of these, scarcely extensile, and provided with terminal suctorial 

 capitula. 



The beautiful observations of Dujardin on the production of free medusas from their hydroid 

 trophosomes were among the first which made us acquainted with this remarkable phenomenon, 

 and among these his observations on Cladonema are perhaps the most interesting.' 



^ 'Ann. des Sc. Nat.,' vol. xx, 1843, p. 370, and vol. iv, 1845, p. 271, pis. xiv and xv. 



