Egg membrane in V salvator stool?

[Dr Acula]

Hi everyone! Found this in my V salvator's water basin. I fed it a couple of quail eggs the other day so I'm assuming this is just some of the left overs and not a slug. Also the salvator in question is barely 3 feet in length, so I doubt it would be producing eggs at this size. If this is left over from the quail egg, why is that so? Is the membrane not digestable?

 

[Najakeeper]

This one is a mystery... As far as I know, V.salvator females reach sexual maturity quite early and can breed as small as 50cm (snout to vent excluding tail) but that doesn't look like a slug to me. On the other hand, I wouldn't know how an egg membrane passes through the digestive track without getting digested...