Kalmar "euglenid" tana nufin memba na phylum Euglenozoa, wanda rukuni ne na unicellular, flagellated microorganisms. Euglenids suna da nau'in membrane mai sassauƙa wanda ke ba su damar canza sura, kuma suna da flagella ɗaya ko biyu don motsi. Ana samun su da yawa a cikin ruwa mai tsabta kuma sune muhimmin sashi na yanayin yanayin ruwa. Wasu nau'in euglenids suna da hotuna da kuma iya samar da nasu abinci ta hanyar photosynthesis, yayin da wasu kuma heterotrophic ne kuma suna ciyar da wasu ƙananan ƙwayoyin cuta.