(1696) Now when this summer I saw three of the said Fishes for sale , I gave orders to keep the heads for me .I again observed through the magnifying glass the extremities of the said spines which I said cause the pain in stinging , and this with the same result as above .But when I let my eyes roam somewhat away from the extremity , I saw that the said spines or stings were covered with a membrane that was speckled , and that under that membrane , on both sides of the spines or sting there were deep grooves or cuts , which extended along the length of the stings and were partly filled with a transparent aqueous substance ( as it appeared to the naked Eye ) .