Nausithoe racemosa (Komai, 1936)

(Fig. 13)

Stephanoscyphus racemosus Komai, 1936: 182 .

Nausithoe racemosa — Jarms, 1990: 11.

Holotype not known, possibly not extant.

Material examined: Living polyps kept in laboratory cultures (Shirahama, Japan, 2004; 5m depth; S. Kubota col.) .

Diagnosis: medusoid—no gastric filaments, developed mouth or tentacles; polyp—colonial without internal cusps and broad oral disc with small tentacles.

Description: Based on original description, and Werner (1970, 1971, 1973). A reduced medusa, medusoid with no gastric filaments, developed mouth or tentacles; males develop four elongated gonads while in the strobilation chain, so that the upper distal medusoid releases the spermatozoa before the others; females detach before shedding the large size eggs from the mouth, embedded in a mucus strand with nematocysts; the medusoid has a welldeveloped muscular system, but is not able to swim. Polyp colonial; there is a central/primary polyp from which secondary polyps emerge, as a “stem with nodes”, not randomly, but at an oblique angle; no internal cusps; soft body with enlarged oral crown, broad ring around the mouth and small delicate tentacles; the tentacle’s crown has kind of a square shape; dark yellow/brown coloration of tissues due to the large amount of as-yet uncharacterized algal symbiont.

Type locality: Seto, Japan.

Distribution: Japan, NW Pacific Ocean (shallow waters).

Remarks: This species is easily differentiated from other Nausithoe because of the colony’s structure and the polyps’ enlarged oral crown and small tentacles.