Help with egg ID, snail?

Anyone recognize this type of egg? Quite a few of my Astrea snails were up on the glass last pm, and today many of these were found. They are about 1.5mm total size, with the tiny internal individual eggs.

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Ken

All but one of the egg cases are gone today.

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Ken

Responses are always a bit slower for inverts. Not too many people have done them. I am thinking Umm_fish is the most experinenced invert guy. I may be completely off on that though.

Maybe post pics of the adult snails you have?  

Th snails I have in the tank are Astrea, cerith, nassarius, and trochus. That is, the ones I have purchased. It's always possible there has been a random hitchhiker, but I haven't added any rock or coral in over a year.

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Ken

i have nerite snails and their eggs look almost like that, but the case is opake and the eggs are yellow. cerith snails lay long strings of eggs, so they are not serith eggs.
i had my nassarius snails lay eggs on the inside of my overflow covers, how they managaed that i have no clue, and they looked like mini mermaid cup algae. one sac of those eggs had developed into three snails with shells inside the tiny case, but when i went to pick it off for pictures i crushed the shells because they were so fragile. so either astrea or trochus.
 

It is not a Trochus. They are pelagic spawners.