The prostomium (From Ancient Greek, meaning "before the mouth"; pl.: prostomia; sometimes also called the "acron") is the cephalized first body segment in an annelid worm's body at the anterior end. It is in front of (but does not include) the mouth, being usually a small shelf- or lip-like extension over the dorsal side of the mouth.

The meaning of PROSTOMIUM is the portion of the head of an annelid worm (such as an earthworm) that is situated in front of the mouth.

The first segment, the prostomium, is in front of the mouth and may be a simple lobe or a highly developed projection. The next segment, the peristome, surrounds the mouth and is followed by a series of segments, the total number of which may be limited or unlimited.

Sep 22, 2017 · The main difference between prostomium and peristomium is that prostomium is in front of the mouth of the annelids whereas peristomium surrounds the opening of the mouth. The prostomium consists of sensory organs which help annelids to thrust into the soil.

The prostomium is the most anterior pre-segmental part of the body to the mouth, which may or may not be retractile and often bears antennae, eyes, tentacles, and palps. The antennae have sensory organs, and the palps may be sensory or can be used as feeding appendages.

Oct 27, 2023 · Prostomium refers to the anterior, pre-mouth portion of an annelid worm, while peristomium is the segment that surrounds the mouth. In the intricate world of annelid anatomy, the prostomium and peristomium are two fundamental terms describing different parts of these segmented worms.

Some species of earthworms have a tongue-like lobe above the mouth called prostomium. The prostomium is actually a sensory device. Earthworms do not have a nose, eyes, ears, or hands to gather sensory information about their environment.

Prostomium definition: A small, noselike portion of the first body segment in many annelid worms, lying above and overhanging the mouth in earthworms.

The anterior portion of the head of an annelid worm, situated in front of the mouth. The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved. that part of the head of some annelids and molluscs which lies in front of the mouth.

PROSTOMIUM definition: the lobe at the head end of earthworms and other annelids : bears tentacles , palps ,... | Meaning, pronunciation, translations and examples