a thin membrane chiefly found in the bird and fish kind, which covers the eyes of these animals, sheltering them from the dust or too much light; yet is so thin and pellucid, that they can see pretty well through it.

(a) This gentleman was cotemporary with Sir Hans Sloane. He was a man of great probity, an able physician, and a skillful naturalist. He collected and arranged a number of the plants of Jamaica, which he presented to Dr Sloane, and made several communications to the Royal Society.