TOL. XLIII.] PHILOSOPHICAL TRANSACTIONS. 77 



to which has afterwards been given new water from the ditch, have soon after 

 began to multiply again. 



These polypi are capable of swimming about; and when they swim, they are no 

 longer in clusters, but always single; and they do not then appear in the same 

 form as when they are fixed, and open at their anterior ends. It is by swimming 

 that they leave the place to which they first appeared fixed, and that they go and 

 fix themselves to any other body that they find in their way. 



We should begin to observe a polypus soon after it has fixed itself singly, in 

 order to see regularly in what manner the clusters form themselves, and in what 

 way these small creatures multiply. The stem or pedicle of a polypus that is yet 

 single, and which has but lately fixed itself, is at first very short, but lengthens 

 itself in a little time. After that, the polypus multiplies ; that is to say, it di- 

 vides or splits itself into two lengthwise. The lips are first drawn into the body, 

 whose anterior part closes, and becomes round : the motion that was to be seen 

 before the lips were drawn in, no longer appears; yet we may see, by looking 

 with attention, a slow motion within the body, during all the time that the polypus 

 remains closed. The anterior part of the polypus flats itself afterwards by degrees, 

 and spreads in proportion, becoming broader as it shortens; it then gradually 

 splits down through the middle, that is, from the middle of the head to the place 

 where the posterior end joins to the pedicle: so that, in a little while, there ap- 

 pear two separate round bodies joined to the extremity of the pedicle that just be- 

 fore supported but one. 



The anterior part of each of these bodies then opens by degrees; and, as they 

 open, the lips of the new polypi show themselves more and more. Then is the 

 time of observing these lips with attention, and of forming an idea of their true 

 form, and of their motion. This motion is at the first very slow, it quickens as 

 the polj^i continue to open ; and, as soon as they have done, it becomes as swift 

 as that which appeared in the lips of the whole single polypus, before it began to 

 divide: and then these new polypi may be considered as entirely formed. They 

 are at first less than the polypus from which they were formed ; but they grow to 

 the same size in a very little time. A polypus is about an hour in dividing itself. 



The lips of these polypi appear to be composed of 4 or 5 transparent stripes, 

 having all an undulating motion. While the polypi are opening, and that the 

 motion of their lips is yet but slow ; we see on either side, when they are in a cer- 

 tain position, what seem to be the wheels of a mill, in the polypi that are quite 

 formed, and whose lips move very fast : but we now see, while they are opening, 

 what may be rather taken for 4 or 5 fingers on either side of their mouths ; which 

 alternately bend down and extend themselves every instant, and to which the 

 transparent stripes abovementioned appear to be fixed. 



When the first polypus is thus divided, and the two new ones produced by this 



