External morphology long, and between 0-2 and 0-6 cm Thickly encrusting sponges, between 5 and 8 cm individuals are thick, growing around vestimentiferan tubes (Figure 1A-F. Living smooth to the cream colour and have a soft, crumbly texture. The sponge surface is touch, although slightly uneven in places and in some areas. Oscules and ostioles are simple pore-like perforations, scattered across the sponge surface (Figure om ostioles in fixed animals, major oscules can usually be identified by the presence of a surrounding radial pattern of transparent excurrent canals. Major oscules range from um in diameter. The remaining perforations on the sponge surface range from 150 to 400 um, and correspond to either smaller oscules, ostioles or inhalant canals where the ectosome is broken or by The smaller oscules are sometimes very close together especially when sharing a common subectosomal space. In such cases, they are strands. separated from each other only by thin