In the Calyptoblastea the perisarc is always continued above the From Allman's Gymnoblastic Hydroids, by permission of the Council of the Ray Society.
The polyp may then form a second bud, which becomes the starting point of a new system, the beginning, that is, of a new branch; and even a third bud, starting yet another system, may be produced from the same polyp. Hence the colonies of Calyptoblastea may be com plexly branched, and the bud ding may be biserial through out, uniserial throughout, or partly one, partly the other.
5), the blastostyles gradually lose their nutritive function and the organs connected with it; the mouth and tentacles disappear, and the blastostyle obtains the nutriment necessary for its activity by way of the coenosarc. In the Calyptoblastea, where the polyps are protected by special capsules of the perisarc, the gonothecae enclosing the blastostyles differ from the hydrothecae protecting the hydranths (fig.
SUB-ORDER HYDROIDEA CALYPTOBLASTEA (LEPTOsome with polyps always differentiated into nutritive and reproductive individuals(blastostyles) enclosed in hydrothecae and gonothecae respectively; with sympodial type of budding.
In many Calyptoblastea there occur also reduced defensive polyps or dactylozoids, which the special name of sarcostyles.
At present, ten recent and one extinct family of Calyptoblastea (Leptomedusae) may be recognized provisionally: 1.
It can only be said that their organization, so far as the state of their preservation permits it to be ascertained, offers closer analogies with the Hydrozoa, especially the Calyptoblastea, than with any other existing group of the animal kingdom.