peristome


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Related to peristome: calyptra

per·i·stome

(per'i-stōm),
A groove leading from the cytostome in ciliates and certain other forms of protozoa.
Synonym(s): peristoma
[peri- + G. stoma, mouth]

peristome

(pĕr′ĭ-stōm′)
n.
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.

peristome

(pĕr′ĭ-stōm) [″ + stoma, mouth]
The channel leading to the cytosome or mouth in certain types of protozoa.

peristome

any structure that occurs around the mouth or opening of an organ.
References in periodicals archive ?
Peristome entire, incrassate, proportionally small, roundish in outline, about as high as wide or wider than high, PH: PW 0.
Remarks: P atewaensis resembles P liberiana, sharing a strait palatal lip, a proportionally small, rounded peristome and close-set axial ribs on the teleoconch.
Diagnosis: Differs from the similarly sized P atewanensis by the less elongate shell with lower protoconch; peristome proportionally larger and less rounded, with the palatal lip curved in lateral view.
Peristome entire, not strongly incrassate, squarish in outline, higher than wide; PH:PW 1.
These shells differ from those of P atewanensis and P liberiana by a comparatively less irregularly coiled protoconch (resulting in a flatter apex which seems less conspicuous distorted in lateral views), a higher than wide peristome, and by a distinctly curved, forward arching palatal lip (in lateral view).
Aperture ovate-reniform, peristome strongly oblique to vertical axis of shell, interrupted by base of penultimate whorl; outer lip simple and thin; upper part of columella lip reflected and partially covering umbilicus.
1: No basal -- x spiral sculpture; peristome partially reflected over umbilicus and forming flat plate.
2) in its small size but differs in having better developed peristomes with an undulating edge.
The edges of peristomes can form spines like in Conchicolites sp.
subacuminata in having closer-set axial ribs on the teleoconch, a less acuminate apex, less tightly coiled whorls, and a proportionally larger peristome.
Peristome complete in holotype (not in other specimen, measurements are estimates), somewhat higher than wide, PH:PW in holotype 1.
Peristome complete, roundish to (mostly) somewhat higher than wide; PH: PW 0.