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.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
Pedicels with thick perisarc, strong, straight or slightly sinuous, relatively short, 1.1-2.6 mm high, 65-88 [micron]m in maximum diameter; group of 18-20 strong annuli placed basally, and of 20-22 distally; usually smooth in between, but occasionally slightly waved.
Hence, the pattern of the perisarc emerges exclusively at that site.
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.
On either side of the basal disc just above the substrate attachment zone, the perisarc is connected to the basal disc and lower body column.
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.