prostomium

American  

[proh-stoh-mee-uhm] / proʊˈstoʊ mi əm /

noun

plural

prostomia

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

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prostomium British  

/ prəʊˈstəʊmɪəm /

noun

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

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Other Word Forms

• prostomial adjective

Etymology

Origin of prostomium

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

Example Sentences

Nerve cord lies in coelom; brain in first segment or prostomium in many forms.

From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 7 "Cerargyrite" to "Charing Cross" by Various

It is, however, always possible to recognize a head, which consists at least of the peristomial segment with a forward projection of the same, the prostomium.

From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 7 "Cerargyrite" to "Charing Cross" by Various

About 1870 the question arose for discussion whether the somites in front of the mouth are to be considered as derived from the prostomium of a Chaetopod-like ancestor.

From Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 6 "Armour Plates" to "Arundel, Earls of" by Various

Tomopteris is remarkable for the fact that the hammer-shaped prostomium has paired ventral processes each with a single seta.

From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 7 "Cerargyrite" to "Charing Cross" by Various

The peculiar prostomium of Tomopteris is described below.

From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 7 "Cerargyrite" to "Charing Cross" by Various