ZOOPHYTES. 841 



animal, and surrounded by protrusile, contractile, and 

 expansile fleshy lips. I have several times seen this 

 mouth opened, and partly turned outwards, in kindred 

 species ; and once I had an opportunity of witnessing a 

 quite unexpected use to which it was applied, viz., that of 

 a great sucking disk. I had put the animal in such a 

 live-box as this — the two glass surfaces being just suffi- 

 ciently wide apart to allow it free liberty to turn about in 

 all directions as far as it wished. On my looking at it 

 after a momentary interval, I saw that the extremity had 

 suddenly become a large circular disk of thrice the dia- 

 meter of the body : its substance was gelatinous, full of 

 granules, arranged concentrically. I neither saw this disk 

 evolved nor retracted ; but after some time, on looking at 

 it, the same phenomenon was repeated. In order to ob- 

 tain a better sight of it, but without suspicion of what I 

 was about to effect, I slightly turned the tube of the box, 

 carrying with it the sea-weed to which the polype was 

 attached, my eye upon it attentively observing all the 

 time. The base of the polype moved away from its posi- 

 tion, but the broad disk was immovable. I continued to 

 turn the upper glass, until at length the body was dragged 

 out so as to be considerably attenuated ; still the disk 

 maintained its hold on the lower glass, with no other 

 change than that of being elongated in the direction in 

 which it was dragged. At length it slowly gave way", and 

 resumed its original shape by gradual and almost imper- 

 ceptible diminution of the circumference. 



Around this expansile, but now fast closed mouth, you 

 observe four tentacles, radiating in a plane at right angles 

 to the axis of the thread, towards the four cardinal points ; 

 they are long, slender, straight, and each is terminated 

 by a globose head of considerable size, resembling the 

 arms of certain screw-presses, which are loaded with ter- 

 minal globes of metal to increase their impetus when 

 turned. 



