To establish the exact relationship it is necessary not only to breed but to rear the medusa, which cannot always be done in 1 In some cases hydroids have been reared in aquaria from ova of medusae, but these hydroids have not yet been found in the sea (Browne [Io a]).
In the Calyptoblastea the perisarc is always continued above the From Allman's Gymnoblastic Hydroids, by permission of the Council of the Ray Society.
Protohydra occurs in oysterbanks and Monobrachium also grows on the shells of bivalves, and both these hydroids probably fish in the currents produced by the lamellibranchs.
From Allman's Gymnoblastic Hydroids, by permission of the Council of the Ray Society.
The buds may all become detached after a time and give rise to separate and independent individuals, as in the common Hydra, in which only polyp-individuals are produced and sexual elements From Allman's Gymnoblastic Hydroids, by permission of are developed the Council of the Ray Society.
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