| Species name | Common name | Distribution | Max. Length (cm) |
|---|---|---|---|
| Synthecium dentigerum Jarvis, 1922 |
Eastern Central Pacific | ||
| Synthecium elegans Allman, 1872 |
Southwest Pacific | ||
| Synthecium formosum (Fewkes, 1881) |
Southwest Atlantic | ||
| Synthecium marginatum (Allman, 1877) |
Western Central Atlantic | ||
| Synthecium megathecum Billard, 1925 |
Eastern Central Pacific | ||
| Synthecium orthogonium (Busk, 1852) |
Pacific | ||
| Synthecium protectum Jäderholm, 1903 |
Fishbone hydroid | Southwest Atlantic, Southeast Pacific and the Antarctic | |
| Synthecium samauense Billard, 1925 |
Central Pacific | ||
| Synthecium symmetricum Fraser, 1938 |
Eastern Pacific | ||
| Synthecium tubithecum (Allman, 1877) |
Western Atlantic |