Prostomial
Prostomial is an adjective used primarily in zoological anatomy to describe structures related to the prostomium, the anterior-most part of certain invertebrate animals, such as annelids, polychaetes, and some arthropods. The prostomium is a distinct head-like region that often houses sensory organs, mouthparts or tentacles, and sometimes a prostomium shield that projects forward. When features or processes are described as prostomial, they are typically located on or projecting from this anterior region.
In annelid morphology, a prostomial tube or appendage might be referred to as a prostomial process or
Etymologically, prostomial derives from the Greek prostomion, meaning “forward mouth,” combined with the English adjectival suffix