Masses of eggs.

I've never come across these before. They are egg masses laid by a water snail, Lymnaea stagnalis, sometimes known as the the great pond snail. My garden pond is full of these snails this year and there are large quantities of the egg masses laid on leaves which have fallen in the water.

When out of the water the egg masses look like transparent jellies, up to about an inch long.

There can be up to 120 eggs in each mass! So plenty of snails next year.