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.
References in periodicals archive ?
Descriptions of this species, prostomium elongate are rounded anteriorly, flanked laterally by peristomial ridges leading to ventral mouth.
Body straight and white, resembling a boon of flax, segments extended; anteclitellar portion tapering; prostomium conical, sharp, often ending with a small knob (Fig.
Body wall thin and transparent, both epidermis and longitudinal musculature 7-9 [micro]m thick; in prostomium and clitellum epidermis is thicker.
The sole other enchytraeid species known to have a distinctly pointed prostomium are the deep-sea North Atlantic Grania papillinasus and G.
The six cirratulids gathered were identified as adults belonging to the genus Dodecaceria, mean size 15 mm ([+ or -] 3), characterized by a blunt prostomium forming a hood over its mouth.
kelleri Michaelsen, 1892 in its size and colour, but clearly differs from it by the higher number of spermathecae (1-3 per side in kelleri, 6-9 in proboscideus) and the presence of two prominent probosces on the prostomium.
Prostomium bifid, with caruncle extending to posterior margin of chaetiger 3; no occipital tentacle; no eyes; no pigmentation (Fig.
Prostomium notched, caruncle extends to posterior margin of chaetiger 3, but to end of chaetiger 2 in one specimen; no occipital tentacle; in holotype two pairs of eyes arranged in trapezoid, 0-2 pairs in others, posterior pair larger; no pigmentation (Fig.
The species resembles all other members of this group in having a notched or bilobed prostomium, modified spines with a collar on the convex side of the curved end of the spine, and hooded hooks from chaetiger 7.
Prostomium rounded, entire; caruncle extending to end of chaetiger 2; no occipital tentacle; holotype with three eyes (Fig.