Unknown Dragons (Books)

There is a picture of two Nanodragons in "The Complete Book of Dragons" that are not named or discussed. They are Nanodragons, because they are shown in that section of the book. These two are very similar, with the main feature being that they have a snail's shell as part of their bodies. However, one dragon has two eyes and the other has three eyes, each on stalk like a snail. Whether these are meant to be the same species or two related species, we may never know.