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 (mĕz′ə-zō′ən, mĕs′-)
Any of various small wormlike animals that are parasites of marine invertebrates and have an inner layer of one or more cells surrounded by an outer layer of ciliated cells.

[From New Latin Mesozōa, former phylum name : meso- (because the animals were considered to be intermediate between the protozoans and the metazoans in structure) + -zōa, pl. of -zōon, animal; see -zoon.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Animals) any of several wormlike parasites of the group Mesozoa that live in marine vertebrates
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
Sexually mature individuals with cell numbers below this threshold have so far been reported only from secondarily simplified, commensal, or parasitic species with very simple bodyplans, such as the mesozoan dicyemids, which live in the kidneys of benthic cephalopods and consist of only 10 to 40 cells (4).
The phylogenetic position of dicyemid mesozoans offers insights into spiralian evolution.
Syncytia, while uncommon among vertebrates, do occur in a variety of animals including flatworms, mesozoans, and insects (Barnes, 1980).
Patterns of cell division and cell lineages of the vermiform embryos of dicyemid mesozoans were studied in four species belonging to four genera: Conocyema polymorpha, Dicyema apalachiensis, Microcyema vespa, and Pseudicyema nakaoi.