| Species | Name Used |
|---|---|
| Synoicum derjugini Redikorzev, 1927 | Synoicum derjugini (p. ) |
| Synoicum irregulare Ritter, 1899 | Synoicum irregulare (p. ) |
| Synoicum kincaidi (Ritter, 1899) | Synoicum kinkaidi (p. ) |
| Synoicum parfustis (Ritter & Forsyth, 1917) | Synoicum parfustis (p. ) |
| Synoicum pellucidum (Ritter & Forsyth, 1917) | Synoicum pellucidum (p. ) |
| Synoicum sabuliferum Redikorzev, 1927 | Synoicum sabuliferum (p. ) |
| Synoicum sagamianum Tokioka, 1963 | Synoicum sagamianum (p. ) |
| Synoicum solidum Redikorzev, 1937 | Synoicum solidum (p. ) |
| Trididemnum microzoa (Redikorzev, 1913) | Trididemnum microzoa (p. ) |
| Trididemnum opacum (Ritter, 1907) | Trididemnum opacum (p. ) |
| Trididemnum strangulatum (Ritter, 1901) | Trididemnum strangulatum (p. ) |
| Trididemnum tenerum (Verrill, 1871) | Trididemnum tenerum (p. ) |