I don't think these will be easy, but the bladed knop under the bowl is fairly distinctive, and the polished Pontil, together with a nice ring, suggests quality. Are there any variations in the making.....such as slight differences in foot size, or size of knop, or rim diameter? I can't make out the foot due to the grain of the wood of the table.....any wear marks? Is the crystal bright and clear?
It might be a case of trawling the replacements site for martini or cocktail glass, but start with ones that don't sign their pieces. Unless you think they could be earlier as, for example, Stuart didn't sign before 1927.
I keep looking at the pictures and, for no reason I can explain, I'm wondering if they could be French?