placoid
[plak-oid]
- platelike, as the scales or dermal investments of sharks.
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Origin of placoid
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for placoid
Historical Examples
The Thornback Skate is covered with prickles (placoid scales).
Stories of the Universe: Animal LifeB. Lindsay
The teeth of Selachii are fundamentally identical with placoid scales.
The Vertebrate SkeletonSidney H. Reynolds
The most primitive form of the first type of dermal structures is that of the placoid scales of Elasmobranchii.
The Works of Francis Maitland Balfour, Volume III (of 4)Francis Maitland Balfour
In the groups of fishes above the Selachians, the coating of placoid elements shows various modifications.
In the Selachians the bony skeleton is restricted to the placoid elements.
placoid
- platelike or flattened
- (of the scales of sharks and other elasmobranchs) toothlike; composed of dentine with an enamel tip and basal pulp cavity
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Word Origin
C19: from Greek plac-, plax flat
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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