planarian

[ pluh-nair-ee-uhn ]

noun

, Zoology.

1. any of various free-swimming, mostly freshwater flatworms of the class Turbellaria, having an undulating or sluglike motion: popular in laboratory studies for the ability to regenerate lost parts.

planarian

/ pləˈnɛərɪən /

noun

1. any free-living turbellarian flatworm of the mostly aquatic suborder Tricladida, having a three-branched intestine

planarian

/ plə-nâr′ē-ən /

1. Any of various small, chiefly freshwater flatworms of the class Turbellaria, having soft, broad, ciliated bodies shaped like a leaf. Planarians have a mouth on their lower side that is often closer to the tail than the head, and a three-branched digestive cavity. If a planarian is cut into several pieces, each piece can grow into a whole new organism.

Word History and Origins

Origin of planarian¹

1885–60; < New Latin Planari ( a ) a flatworm genus (noun use of feminine of Late Latin plānārius level, on level ground; taken to mean “flat”; plane ¹, -ary + -an

Word History and Origins

Origin of planarian¹

C19: from New Latin Plānāria type genus, from Late Latin plānārius level, flat; see plane ¹

Example Sentences

Chromatic jamming appears to be key to how the planarian brain comes together, guiding single cells into neighborhoods that are a driving force in organ development, he says.

From Science News

Slice a planarian into pieces and, within a week or two, each chunk will grow into a new flatworm — head and all.

From Science News

Wang uses statistical physics to figure out how planarians regenerate entire organs cell by cell.

From Science News

Flat against the stone and not easily perceived may be a chiton, a planarian worm, or a nudibranch.

From Project Gutenberg

It is now nearly forty years since the presence of chlorophyl in certain species of planarian worms was recognized by Schultze.

From Project Gutenberg

Among the lowest forms of worms are the Planarian worms, already alluded to as examples of the third grade of animal existence.

From Project Gutenberg

These are planarian worms, and though not of prepossessing appearance generally, are extremely interesting animals to study.

From Project Gutenberg

The planarian worms that I have just been telling about are monsters.

From Project Gutenberg