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n. pl. pro·sto·mi·a (-mē-ə)
The anterior portion of the head of an annelid worm, situated in front of the mouth.

[New Latin, from Greek prostomion, mouth, lips : pro-, in front of; see pro-2 + stoma, mouth.]

pro·sto′mi·al (-əl) adj.


n, pl -mia (-mɪə)
(Zoology) the lobe at the head end of earthworms and other annelids: bears tentacles, palps, etc, or forms part of a sucker or proboscis
[via New Latin from Greek prostomion mouth]
proˈstomial adj


(proʊˈstoʊ mi əm)

n., pl. -mi•a (-mi ə)
a small protuberance from the first segment above the mouth in certain worms and mollusks.
[1865–70; < Greek prostómion mouth. See pro-2, stoma, -ium2]
pro•sto′mi•al, adj.
References in periodicals archive ?
zulu Specimens One clitellate; Only one, with and their one with clitellum not maturity developing fully developed tubercula pubertatis Characters Length Large, 185 mm abscised Diameter 12 mm 9-11 mm Prostomium Not observed Epilobous, short, broad Number of Abscised, 135 segments not observed Setae Minute, Minute, only difficult to on some segments, detect closely paired Annulation Not described; 4(?
These worms are smooth-bodied and relatively fragile in comparison with other tubificids, with short postclitellar segments and conical prostomium when fixed in alcohol (Fig.
The shell-boring polychaete species were identified on the basis of fifth setiger chaetae, prostomium and pygidium morphology, and branchiae distribution.
The scientific name for this kind of mouth segment is a prostomium, Jacobs explains.
Prostomium transverse, short, longitudinally striated; dorsal setae of anterior body region single, ventral setae doubled, no setae in posterior body region; ventral tuberculum single.
The specific name naso is a noun derived from the Latin word nasus (nose) and the Roman personal name Naso, emphasizing the nose-like prostomium of this worm.
Morphologically, it is characterized by a blunt prostomium forming a hood over its mouth.
Etymology: From Latin proboscis, referring to the presence of two protrusions on the prostomium.