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Having body tissues derived from three germ layers, the endoderm, mesoderm, and ectoderm, seen in all multicellular animals except certain invertebrates such as the cnidarians and sponges.

[Greek triploos, triple; see pel- in Indo-European roots + -blastic.]

trip′lo·blas′ty n.
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.


(Zoology) (of all multicellular animals except coelenterates) having a body developed from all three germ layers. Compare diploblastic
[C19: from triplo- threefold (from Greek triploos) + -blast]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˌtrɪp loʊˈblæs tɪk)

(of an embryo) differentiating into three primary layers, the ectoderm, endoderm, and mesoderm.
[1885–90; < Greek tripló(os) threefold + blastikós budding]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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References in periodicals archive ?
The origin of muscle from the mesoderm in triploblastic lineages is a central evolutionary question in higher animals.
Hall, "The neural crest as a fourth germ layer and vertebrates as quadroblastic not triploblastic," Evolution & Development, vol.
Triploblastic relationships with emphasis on the acoelomates and the position of gnathostomulida, cycliophora, plathelminthes, and chaetognatha: a combined approach of 18s rDNA sequences and morphology.
acredema and Helicoradomenia sp., were examined by transmission electron microscopy and found to be of a triploblastic metazoan, most probably a polychaete (Todt & Salvini-Plawen 2005).
Despite being trained in comparative anatomy, or perhaps because of it, I was distrustful of some of the morphological criteria - for example, diploblastic versus triploblastic, or proterostome versus deuterostome - used in reconstructing phylogeny.
Whether the cleavages are spiral or not, a major aspect of the evolution of diploblastic into triploblastic Metazoa is the formation of a third germ layer, the mesoderm.
They have a primitive morphology with simple triploblastic bodies (based on body-plan categories).
Triploblastic relationships with emphasis on the acoelomates and the position of Gnathostomulida, Cycliophora, Plathelminthes, and Chaetognafha: a combined approach of I8S rDNA sequences and morphology.
Now that many of the components of innate immunity have been identified in cnidarians, we can begin to assess whether they are performing a role homologous to the role in triploblastic animals.