Spotting

Description:

The organism I want to identify is near the top of the field of view, next to the leaf's vein. It is flattened, oval-shaped, and appears to be soft-bodied. There are two eye-spots on one end, and its body is transparent.

Habitat:

The photo is of the back of a fern leaf at 35x magnification. The structure on the bottom is a sorus. The fern was grown in a greenhouse, so the location may not be relevant.

Notes:

I suspect that this could be a type of terrestrial mollusk. I wouldn't think it's an insect because of the lack of an exoskeleton or jointed appendages, but I suppose it could be a larval arthropod.