prostomium

American  

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

noun

• prostomia
  plural

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

Derived Forms

• prostomial
  adjective

Inflected Forms

Nouns

• prostomia
  plural

Etymology

Origin of prostomium

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

Example Sentences

See Examples For:

prostomium

The parapodia of Chaetopoda are never coated with dense chitin, and are, therefore, never converted into jaws; the primitive “head-lobe” or prostomium persists, and frequently carries eyes and sensory tentacles.

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

The segmentation is of the mesoblast to begin with, and appears later behind the mouth, the part anterior to this becoming the prostomium of the adult.

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

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

Structure.—The body wall consists of an epidermis which secretes a delicate cuticle and is only ciliated in Aeolosoma, and in that genus only on the under surface of the prostomium.

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