Implacentalia

noun plural

in former classifications
: the monotremes and marsupials regarded as a systematic unit characterized by the absence or rudimentary development of a placenta

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Cite this Entry

“Implacentalia.” Merriam-Webster.com Medical Dictionary, Merriam-Webster, https://www.merriam-webster.com/medical/Implacentalia. Accessed 8 Jul. 2026.

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