Rotz-fish (or slime-fishes) I call these, that in themselves are nothing else but slime, and they are transparent. I have observed several kinds of these, some whereof have parts like finns, as that same which I call the sea May-flie. Others are like unto the flat snails, only instead of finns they have stalks like unto feathers. Besides these, I have seen four other sorts that are quite differing in shape from the others, and are called sea-qualms by the seamen, as if they were a thick scum of the sea coagulated together. They are also called after the Latin name sea nettles, because they cause a burning pain like unto nettles. I have formerly had some thoughts that the rotz or slime-fishes might be a seed flung out and so putrefied, and that they did cause this burning pain by reason of their putrefaction; and so I did think they received their shape or form according to the several kind of fishes from whence they came, and that some did take after thornbacks, others after whales, and the like; but this doth not seem to be agreeable to reason, for I have considered it better since, and find life to be a far more noble thing than that it should proceed from putrefied seed cast away.

They cleanse the sea mightily, for all the filth and uncleanness sticks to them just as a burr doth unto cloth.