(Anthomedusae) and only one tentacle.
- Portion of colony of Bougainvillea fruticosa (Anthomedusae-Gymnoblastea) more magnified.
The external form of the Hydromedusae varies from that of a deep bell or thimble, characteristic of the Anthomedusae, to the shallow saucer-like form characteristic of the Leptomedusae.
3 and 22) there is but a single tentacle, while two are found in Amphinema and Gemmaria (Anthomedusae), and in Solmundella bitentaculata (fig.
Hence the gonads are found on the manubrium in Anthomedusae generally; on the base of the manubrium, or under the gastral pouches, or in both these situations (Octorchidae), or under the radial canals, in Trachomedusae; under the gastral pouches or radial canals, in Narcomedusae.
Until quite recently the hydroids (Gymnoblastea) and the medusae (Anthomedusae) have been classified separately, since the connexion between them was insufficiently known.
The Leptomedusa in form is generally shallow, more or less saucer-like, with velum less developed than in Anthomedusae (fig.
The Siphonula produced buds on the manubrium, as many Anthomedusae are known to do, and these by reduction or dislocation of parts gave rise to the various appendages of the colony.
Orders: Eleutheroblastea, Hydroidae seu Leptolinae (Sub-orders: Anthomedusae, Leptomedusae), Hydrocorallinae, Graptolitoidea Trachylinae (Suborders: Trachomedusae, Narcomedusae), Siphonophora.