150 
SUPPLEMENT. 
2. Myriozoum gracilis {Michelin,) Dana. — Whitish; dichotomously ra- 
mose, branches slender, terete, above irregularly inflated, round truncate at t 
apex. 
Mediterranean. — Michelin. 
Genus PUSTULOPORA.— Blainville. 
Attached. Coralla calcareous, consisting of a series of layers, I 
cylindrical or sparingly ramose ; cells scattered, a little promi- 
nent or pustuliform, aperture circular. 
Genus COSCINOPORA.— Goldfuss. 
Attached, cyathiform or incrusting. Coralla calcareous, con- 
sisting of fibriform tubes ; cells immersed and arranged in quin- 
cunx order, funnel-shape ; interstices narrow. 
Genus RECEPTACULITES.— Defrance. 
Coralla calcareous, with quadrangular and nearly contiguous 
cells. 
Genus TETRABIUM. — Dana. 
Coralla massive, consisting of 4-sided tubes, and cells with 
very thin septa or parietes ; cells stellate, with 4 narrow lamellae. 
Genus THEONEA. — Lamouroux. 
Quite small. Coralla calcareous, lobulato-glomerate and la- 
cunose ; cells opening at the summits of the prominences, tubu- 
lar without lamellae ; interstices very thin, naked, and smooth. 
