in Language

Engraved Gourds?

In his Commentary on Jonah, Jerome refers (4:6) to “gourds of small cups/vessels” on which images of the Apostles are sketched:

Et revera in ipsis cucurbitis vasculorum, quas vulgo saucomarias vocant, solent apostolorum imagines adumbrari…

I’d never heard of such an object. Has anyone else, and can you point me to where I might go to find out more?