hydrotheca


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Related to hydrotheca: perisarc

hydrotheca

the cup-like part of the perisarc of colonial COELENTERATES which surrounds and protects the polyp.
References in periodicals archive ?
Oddly, the polyp of Lovenella gracilis Clarke, 1882 is defined by the operculum being a continuation of the hydrothecal wall, therefore lacking a basal line separating operculum and hydrotheca (Calder, 1971, 1975).
Hydrotheca campanulate, 350-740 [micro]m (n = 10) deep from rim to base, 215-340 [micro]m (n = 10) wide at margin, 100-180 [micro]m (n = 10) wide at diaphragm; diaphragm thin, transversal; operculum with 8-11 triangular to pentagonal valves (n = 10), apparently as folded continuation of hydrothecal wall, but with discrete line demarcating operculum from hydrotheca (only in SEM).
One can see in the figures that the older colony elements are unaffected by the treatment: polyps stretch out of their hydrotheca, and they are able to catch their prey.