prostomium


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prostomium

[prō′stō·mē·əm]
(invertebrate zoology)
The portion of the head anterior to the mouth in annelids and mollusks.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Prostomium rounded with two lateral and one shorter median antenna arising from the posterior margin of the prostomium, and a pair of palps.
Interestingly, a similar plasticity is hypothesized for the ontogeny of the operculum, being derived from a radiole in the SerpulalHydroideslCrucigera clade in serpulins but a de novo development from the prostomium in spirorbins (Brinkmann and Wanninger, 2009).
Descriptions of this species, prostomium elongate are rounded anteriorly, flanked laterally by peristomial ridges leading to ventral mouth.
The prostomium is blunt, conical, the length being slightly longer than width and has no eyes and appendages.
This statement disagrees with that outlined by Eliason (1920) and Thulin (1921), according to Jones (1956), who mentioned that the prostomium had a transverse furrow, giving the erroneous impression that the proximal part was an asetigerous segment.
Selected animals were placed in ethanol solution (5%) and dissected to extract the male reproductive organs, located between the prostomium and the clitellum.
adventitium crawled anteriorly on the earthworm and "capped" the prey's prostomium, peristomium and anterior segments with its own head and anterior body.