orthis


From The Collaborative International Dictionary of English v.0.48:

Orthis \Or"this\ ([^o]r"th[i^]s), prop. n. [NL., fr. Gr. 'orqo`s
   straight.] (Zool.)
   An extinct genus of Brachiopoda, abundant in the Paleozoic
   rocks.
   [1913 Webster]
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