perisarc


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Related to perisarc: Coenosarc

perisarc

the horny covering of hydrozoan coelenterates of the orders Gymnoblastea, Calyptoblastea and Hydrocorallinae. In the latter, the perisarc is massive and impregnated with calcium.
References in periodicals archive ?
Our interest is to learn how the perisarc is shaped.
To test whether a differential hardening of the perisarc could play a role in the process of shaping, we treated the colonies with substances that could be expected to either support or to antagonize the hardening process.
During formation of the smooth part of a shoot, the tissue tube in the tip is about 160-250 [micro]m in diameter and is in tight contact with the perisarc over a length of 250-350 [micro]m (the perisarc is translucent).
The composition of the perisarc is not well known but includes chitin and proteins (Jeuniaux, 1963; Chapman, 1973).
The treatment stains the perisarc of the tip and in particular the outer surface of all ectodermal cells in the tip, that is, in the region in which all ectodermal cells contact the perisarc.
Although the perisarc looks almost uniform within an internode, it is not.
Thus, the application of L-cysteine may antagonize perisarc hardening if the formation of disulfide bonds is involved in this process.
The perisarc tube widened, crumbled, and displayed folds at unusual positions (Fig.
Although the shape of the perisarc was altered to a great degree, the sequence of the pattern elements--such as the proximal annulated zone, the smooth part, the distal annulated zone, and the hydrotheca-- was laid down as usual.
Phenylthiourea, due to its sulfhydryl moiety, was also expected to interfere with the hardening of the perisarc.
The basal disc contains a large number of ectodermal bipolar and multipolar ganglion cells [ILLUSTRATION FOR FIGURE 26 OMITTED], and multipolar ganglion cells are abundant in the region of perisarc attachment to the basal disc and lower body column [ILLUSTRATION FOR FIGURE 22 OMITTED].
A mouth is present at the very tip of the head just above the whorl of capitate tentacles, and a perisarc covers the stalk and basal region of the polyp.