prostomium

[ proh-stoh-mee-uh m ]

/ proʊˈstoʊ mi əm /

the unsegmented, preoral portion of the head of certain lower invertebrates.

Origin of prostomium

1865–70; < New Latin < Greek prostómion mouth. See pro-², stoma, -ium

pro·sto·mi·al, adjective

Prostomium: The region in front of the mouth; the preoral part of the head.

The Sea-beach at Ebb-tide |Augusta Foote Arnold
Prostomium wider than long, deeply bilobed, the median tentacle inserted deeply in the intervening incision.

Journal of Entomology and Zoology, Vol. 11. No. 1. |Various
Prostomium of usual general form; consisting of fourteen or fifteen rings.

Journal of Entomology and Zoology, Vol. 11. No. 1. |Various
Prostomium with a lateral process or horn on each side in front, notched in front at middle.

Journal of Entomology and Zoology, Vol. 11. No. 1. |Various

Prostomium generally small, sometimes prolonged, but never bearing tentacles or processes.

Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 7 |Various

prostomium

/ (prəʊˈstəʊmɪəm) /

the lobe at the head end of earthworms and other annelids: bears tentacles, palps, etc, or forms part of a sucker or proboscis

prostomial, adjective

via New Latin from Greek prostomion mouth