76 
aut: 
HISTORY OF BRITISH ZOOPHYTES. 
generally strengthened with a horny or calcareous axis, 
enveloped with the gelatinous or creto-gelatinous crust, 
in which the polypes are immersed, and which open on 
the surface in a starred fashion with eight rays. 
HeiantHorpa.—Polypes single, free, or permanently 
attached, fleshy, naked, or encrusted with a calcareous 
polypidom, the upper surface of which is crossed with 
radiating lamelle; mouth encircled with tubulous 
tentacula; stomach membranous, plaited ; intestine 0 ; 
anus 0; oviparous ; the ovaries internal. 
