ZOOPHYTES 886- 



in the middle and rounded at the end, and many of the 

 heads, which are more ventrieose than the rest, contain a 

 bubble of air in the centre. This air is doubtless taken 

 in at the mouth, which is situated at the extremity; for, 

 though you can discern no perforation, yet there is aa 

 aperture capable of being opened widely at the pleasure of 

 the animal, and surrounded by protrusile, contractile, and 

 expansile fleshy lips. I have several times seen this mouth, 

 opened, and partly everted, 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 sufficiently 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 cir- 

 cular disk of thrice the diameter of the body: its sub- 

 stance was gelatinous, full of oblong granules, arranged 

 concentrically. I neither saw this disk evolved nor re- 

 tracted; but after some time, on looking at it, the same 

 phenomenon was repeated. In order to obtain 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 alga to which the polype was attached, my eye upon 

 it, attentively observing all the time. The base of the 

 polype moved away from its position, but the broad disk 

 was immovable. I continued to turn the upper glass, un- 

 til at length the body was dragged out so as to be consid- 

 erably 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 

 .-SCIENCE 17 



