Also found in: Encyclopedia.


n.1.(Zool.) A brachiopod shell of the genus Orthis, and allied genera, of the family Orthidæ.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
He commented: "These specimens are plainly conspecific with the specimens from the Davidsville Group at Gander Lake, Newfoundland (Blackwood 1982) that remain in "open nomenclature" despite having been identified as a 'Celtic Province' orthid and illustrated twice by McKerrow and Cocks (1977, 1986).
Phylogenetic revision of the Late Ordovician orthid brachiopod genera Plaesiomys and Hebertella from Laurentia.