Vellumnus labyrinthicus (Miers, 1884)

(Figs. 13A, B, 14A–C, 15, 16, 19 B)

Type material. Lectotype (here designated): male (8.5 × 6.8 mm) (NHM 1882.165), Thursday Island, Australia, 3–5 fathoms, coll. HMS Alert. Paralectotypes: 2 females (larger 15.8 × 13.0 mm) (NHM 1882.165), same data as lectotype; 1 male (9.0 × 8.0 mm) (NHM 1882: 93), Port Molle, Australia, 14 fathoms.

Additional material examined. 1 male (9.0 × 8.0 mm) (ZRC 1983.10.14.1), 1 male, 1 female (9.6 × 8.3 mm) (ZRC 1983.10.14.2), from sponge, dredged from shell and gravel bottom, west of Pulau Pawai, Singapore, D. S. Johnson, Dec. 1952; 1 ovigerous female (3.6 × 2.0 mm) (ZRC 1983.10.14.3), between southern islands and Singapore island, 12 Oct. 1953; 1 male (13.9 × 10.0 mm) (ZRC), Cyrene Reefs, Singapore, on Pavona coral, coll. B. Goh, 15 Aug. 1986; 2 males (14.6 × 12.8 mm, 13.5 × 10.8 mm) (ZRC 1999.397), dredge, Pulau Semakau, Singapore, coll. P. K. L. Ng, 1991; 1 female (ZRC 2000.1147), crevices in rock wall, 3 m, northern Pulau Semakau, Singapore, coll. D. Lane, 4 Mar. 2000.

Diagnosis. As for genus.

Remarks. There is some variation in the shape of the G1, with that of the types lacking the small distal flap near the tip, and some specimens having a relatively shorter distal part (Figs. 15 C–E, 16E–G, I, J). These differences, however, appear not to be significant and the specimens from Australia and Singapore agree in almost all other respects.

Lanchester (1900: 743) reports the species from “5–15 fms., rough bottom”. Johnson (1963) reported it as a commensal on sponges, and they have been found in sponges obtained by dredges, although they have also been found in other habitats. Goh et al. (1990) reported specimens obtained from the bases of living subtidal Pavona corals (Agaraciidae) in Singapore; while others have been obtained from rock crevices.