268 HISTORY OF BRITISH ZOOPHYTES. 
Polypidom crustaceous; cells in a single layer. 
LEPRALIA. 
Polypidom crustaceous; cells quincuncial. Mem- 
BRANIPORA. 
Family V. Polypidoms multiform, composed of oblong 
sub-quadrangular cells, disposed in semi-alternating 
series ; the cells conjunct, horizontal to the plane of 
axis, with a subterminal or lateral aperture, usually 
covered with an ovarian capsule. ~ Hscuarips. 
Polypidom foliaceous or membranous, composed of 
several series of oblong sub-quadrangular cells, on 
two planes, or one only. Frusrra. 
Polypidom membrano-calcareous, frondescent; the cells 
immersed, in a double layer placed back to back, 
like the cells in honey-comb. Hscwara. 
Polypidom calcareous, frondescent, netted; the cells 
on the upper side only. Rerrpora. 
Polypidom dichotomous, with jointed cylindrical 
branches; cells immersed, rhomboid. Sanitcornia. 
*%** Polypidoms sponge-like, fleshy, polymorphous; the 
cells irregular in disposition, immersed, with a con- 
tractile aperture; no external ovarian capsules. Hat- 
CYONELLEA, Hhrenb. Corall, 153. 
