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- 



