Found 1 items, similar to aptychus.
English → English (gcide) Definition: Aptychus Aptychus \Ap"ty*chus\, n. [NL., fr. Gr. 'a priv. + ?, ?, fold.] (Zo["o]l.) A shelly plate found in the terminal chambers of ammonite shells. Some authors consider them to be jaws; others, opercula. [1913 Webster] ||