7. Polymastia fistula n. sp. (Figs. 8, 9)

q÷ųāḁḍ(ṳḋ)

Type specimen. Holotype (NIBRIV0000881728), Korea: Sasudo, Chuja-myeon, Jeju-si, Jeju-do, 2 Jun 2013, by SCUBA, depth 30-35 m, deposited in NIBR.

Description. Thick encrusting sponge, size up to 7 × 6 × 0.5 cm. Surface with numerous protruding long and thin noodle-like fistulae, 1-4 cm long, 1.5-2 mm thick, number of fistulae in small sponge 40 and large sponge over 80. Surface between papillae rough due to pieces of shell and sand. Oscules not clear. Color in life yellow. Texture firm, almost incompressible.

Skeleton: Surface of fistulae has small tylostyles and centrotylote microxeas and inside has thick large tylostyles (Fig. 8D). Large tylostyles, 1,100 -1,400 × 15-20 μm, medium tylostyles, 500-700 × 10 μm and small tylostyles, 150-170 × 3-7 μm. Ectoderm of sponge, 2 mm thick, usually radial arrangement of tylostyles (Fig. 8C). Centrotylote microxeas, 70-100 μm.

Etymology. The species name, fistula, is named after sponge shape with numerous long fistulae at the surface.

Remarks. This species has numerous long and thin fistulae at the surface numbering 40-80. The shape of fistulae is very similar to P. lorum . Polymastia lorum has a small number of long papillae (12) and their size of papillae is longer than the new species. In P. lorum, ectodermal layer is common in centrotylote microxeas while in the new species is common through fistulae.