Definition of nemertean in English:


(also nemertine)

Pronunciation /nɪˈməːtɪən//nɛməˈtiːən/


  • A member of the small phylum Nemertea; a ribbon worm.

    • ‘The organization of the body compartment between the epidermis and gut in nemerteans and flatworms also does not reveal a uniquely similar pattern.’
    • ‘Most nemerteans found in San Francisco Bay are very small and not easily identifiable.’
    • ‘Frontal glands have been cited in the classical literature as probable homologues of Platyhelminthes and nemerteans.’
    • ‘Such an association of cells and mechanism of precursor translocation have not been reported from nemerteans previously.’
    • ‘The phylogenetic position of nemerteans remains controversial.’


  • Relating to or denoting nemerteans.

    • ‘Although long considered a character informative for linking nemerteans and platyhelminths, rigorous comparative analyses of protonephridial morphology have revealed no synapomorphies of nemertean and platyhelminth nephridia.’
    • ‘Classical studies revealed that nemertean embryos exhibit spiral cleavage and that the mouth forms at or near the site of the blastopore, but aspects of cell lineage, especially origin of the mesoderm, proved problematic.’
    • ‘The focal stage for this analysis is the early period of embryo encapsulation, a mode of development that has evolved several times among gastropods, polychaetes, nemerteans and flatworms.’
    • ‘Some recent investigations of nemertean development have contributed informative characters for phylogenetic analysis, whereas others have provided insight into developmental mechanisms and patterns.’
    • ‘Consequently, his conclusion that platyhelminths, nemerteans, and rotifers ‘appear to have never had’ a prototroch is not supported by his analysis.’