The molluscs have the widest variety of eye morphologies of any phylum, and a large degree of variation in their function. Cephalopods such as octopuses, squid, and cuttlefish have eyes as complex as those of vertebrates, while scallops have up to 100 simple eyes.
There are between seven and eleven distinct eye types in molluscs. Molluscs have eyes of all levels of complexity, from the pit eyes of many gastropods, to the pinhole eyes of the Nautilus, to the lensed eyes of the cephalopods. Compound eyes are present in some bivalves, and reflective 'mirrors' have been innovated by other lineages such as scallops. As well as varying in complexity, the eyes of molluscs span a huge range in size; they may be from 20 µm (0.02 mm) to 27 cm (11 in) across.
Gastropods and cephalopods have paired eyes on their heads (and sometimes tails), but many molluscs do not have clear head regions in which to locate the eyes. Consequently, many molluscs may have a multitude of eyes in more unlikely places, such as along the edge of their shell.Chitons have a dispersed network of tiny eyes over the surface of their shells which may act together as a compound eye. Many gastropods have stalked eyes; the eye can be retracted into the stalk itself in the presence of danger.
You tickle between my toes,
It's easy when we're alone.
You comfort me while I suffer,
Always enough for you if I am there.
Messing around with you,
Like playing with cats and balls of wool.
You screw up your face with laughter,
Even if after things don't seem quite right.
Something's going on around you,
Makes the leaves on the side of the street skip and dance.
Kick your heels to make me feel good,
It's hard not to feel so shy.
When nothing you say sounds right.
Don't worry if I am boring,
It's only the yawns that make me feel that way.
It's not enough.