Noun
soft unsegmented marine worms that have a threadlike proboscis and the ability to stretch and contract
Source: WordNetThe typical nemertean body is very slim in proportion to its length. citation The smallest are a few millimeters long, citation most are less than convert, and several exceed convert. Source: Internet
Relationships with other phyla English-language writings have conventionally treated nemertean as "primitive" acoelomate bilaterians that are most closely related to flatworms (Platyhelminthes). Source: Internet
Most nemertean species have just one pair of nerve cords, many species have additional paired cords, and some species also have a dorsal cord. Source: Internet