SYNOPSIS. 
1 1 1 1 1 Cells on ringed footstalks. 
Polypidoms confervoid; cells canipanulate ; stem} 
jointed, cells rising from thickened parts off 
the stem .....1 
Laomedea 
Retepora 
Polypidoms confervoid ; cells canipanulate, contin - 1 „ 
nous with the stem, irregular \ campanularia 
* * * Polypidoms internal. 
t Homy, rooted. 
Arborescent, fleshy, warty, with star-shaped de- ) „ 
pressions, rooted \ GoRr ' ONIA • 
1 1 Bony, free. 
Polypidom linear, feathered at one end .... Pennatula . 
Poiypidom linear, with curved lines on either side. Virgularia . 
* * * * Polypidoms external, calcareous. 
Columnar or conical, upper surface lumcllated . . Caryophylua . 
Arborescent, or foliaceons, 3tout ; cells immersed, > 
quincuncial, on the upper side only ... \ ' 
Arborescent, or foliaceons, cells immersed, quin-} „ 
cunical, oval ■ cells on all sides 5 Eschara . . . 
Arborescent, jointed, cylindrical, cells immersed, ( „ 
quincuncial, rlioinboidal ; cells on all sides . . $ v aucimia. . . 
Arborescent, cells oval, distinct and irregularly ) _ 
heaped . . \ Cellepora . . 
Arborescent, confervoid, jointed ; cells tubular, } 
apertures round, terminal. LttISIA - • • • 
Arborescent, confervoid, jointed ; cells oblong, 
apertures opening on one plane J Lellularia . . 
Arborescent, confervoid, jointed ; cells sub-cylin- } 
drical in pairs, apertures lateral and sub-ter- > Notamia . . . 
minal 
Polypidoms creeping, cells erect, spathnlate, aper- ) , 
tures sub-terminal \ Anguinaria. . 
Encrusting, cells tubufar, of equal diameter, dis- } T 
tinct, sometimes ramous J Iubulifora. . 
Encrusting, cells tubular, of equal diameter, co- ) „ 
alesceut Dbcopoba • ' 
Encrusting, cells elliptical, linked together like beads Hippothoa . . 
Encrusting, cells oval, with contracted terminal ) . 
apertures f Lepraeia. . . 
Encrusting, cells oval, with calcareous or ossified J 
rims, apertures patulous J Membranipora. 
Encrusting, cells quadrangular or hexagonal . . . Feustra . . . 
***** Polypidoms spongy. 
Cells immersed, irregular, with contractile apertures Alcyonidium . 
Cells in tubes Crystatella . 
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