Cleavage for mermaids?

The strand was littered with these transparent gelatinous discs of various sizes, from  small coin circumference to the width of my palm (see first extra). Lenslike, they have a slight distorting effect.

They are the remains of  Crystal Jellies  "distinguishable by the fact that you can hardly see any distinguishing characteristics at all".
They aren't true jellyfish but rather colonies of organisms (correctly termed medusae).  They feed on tiny creatures called copepods but their sting is mild and harmless to humans.

At sea they glow in the dark and their spectral presence  means that they are often overlooked and not always recorded. Even when washed up on the shore their translucency makes them  all but invisible.

As you might expect they feel cool and gelatinous but they are not sticky or unpleasant to the touch. They have no smell. I collected several to photograph and laid out together they brought to mind the silicon implants used for breast reconstruction or enhancement such as these.
 I couldn't help thinking of the images of the well-upholstered mermaids that supposedly drove sailors to distraction.

Second extra shows some more. I find them fascinating.