ITS MODE OF FEEDING. 117 find the least heat or stinging follow the contact, even with tender parts of the skin, as the backs of the fingers. Like the Actiniae the Caryophi/llice appear to have a sense of the stimulus of light. They expand most during the night, or in the darkness of a closet ; and I have several times observed that one fully dilated in a dark cupboard would suddenly, on the door being opened, draw in some of the tentacles and perceptibly contract itself, though it might expand again a moment afterwards ; and this in a deep glass vessel, covered with six or eight inches of water, so that no vibration of the air could have been appreci- able. I have not however been able to detect any coloured tubercle at the angles of the mouth, nor any other organs which might be supposed to be analo- gous to eyes. The feeding of the Madrepores afi'ords much amuse- ment ; they are very greedy, and the presence of food stimulates them to more active efforts, and the display of greater intelligence, than we should give them credit for. I put a minute spider, as large as a pin's head, into the water, pushing it down with a bit of grass to a Coral, which was lying with partially exposed tenta- cles. The instant the insect touched the tip of a tentacle it adhered, and was drawn in with the sur- rounding tentacles between the plates, near their inward margin. Watching the animal now with a lens, I saw the small mouth slowly open, and move over to that side, the lips gaping un symmetrically ; while at the same time by a movement as impercepti-