The Collaborative International Dictionary
Metastome
Metastoma \Me*tas"to*ma\, Metastome \Met"a*stome\, n. [NL. metastoma, from Gr. meta` behind + sto`ma mouth.] (Zo["o]l.) A median elevation behind the mouth in the arthropods.
Wiktionary
metastome
n. (alternative form of metastoma English)