macroconch means the female form of an ammonite (that has a larger shell than the male (the microconch).
Etymology
From macro- + conch.
noun
- The female form of an ammonite (that has a larger shell than the male (the microconch).“Initially, the apophysis follows the coiling of the shell but it projects ventrolaterally during the final ontogenetic stage of macroconch development.”