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1. Botany A fringe of toothlike appendages surrounding the mouth of a moss capsule.
2. Zoology The area or parts around the mouth in certain invertebrates.

per′i·sto′mal (-stō′məl), per′i·sto′mi·al (-stō′mē-əl) adj.
References in periodicals archive ?
pulsatoria include antennae about as long as the palps, a smooth anterior peristomial margin which is not projected, and homogomph falcigers with short, slightly denticulated blades.
Descriptions of this species, prostomium elongate are rounded anteriorly, flanked laterally by peristomial ridges leading to ventral mouth.
Avian predators break open the dorsal or ventral surface of the test, or rupture the peristomial membrane and remove Aristotle's lantern (Hendler, 1977; this report).
2004), our study shows N-termVcCentrin4-antibody labels the Vorticella myonemal system composed of longitudinal fibers running from the base of the peristomial disc/lip of the cell body to the junction between the scopular lip and the stalk (Fig.
Tags were implanted into the body cavity of the sea urchins through the peristomial membrane.
Here apical eccentricity refers to the displacement of the apical system on the aboral surface, whereas peristomial eccentricity refers to the displacement of the peristome on the oral surface.
This was done by injecting tetracycline hydrochloride (1 mg/100 mL seawater) through the peristomial membrane.
Diagnosis: The antennae and peristomial cirri are short and the aciculae are black, as are the bidentate subacicular hooks.