VOL. XXIII.J PHILOSOPHICAL TRANSACTIONS. 75 



single fibred root, and raised the plant to the surface. I agree that the leaves, 

 when floating, continue to grow, and may be increased in the manner he men- 

 tions: and I have often taken out of them the young plant which he represents; 

 so that they may be called seeds more properly than leaves ; and my opinion is, 

 that toward the end of the year, on their corrupting, they sink to the bottom, 

 and there take root, so as to continue the succession. 



The animalcula which Mr. L. describes sticking to the root of the plant, I 

 have often observed, not only in water plants, but adhering to the bodies of many 

 sorts of water insects, which I have seen covered almost all over with tufts of 

 them, each tuft consisting of many animalcula, which appear not much unlike 

 the flowers of a lily or fox-glove. 



- This congeries of animalcula will lengthen and contract themselves both alto- 

 gether and severally, and I have observed, when they lie at length, that they 

 extend some extremely minute organs, like small feet (not easily discerned even 

 with my best glasses) which by their quick agitation bring a current of water 

 from all sides toward them. But I never saw that motion in them which Mr. 

 L. says is like that of a mill wheel, nor indeed can I perceive the possibility of 

 such a rotation of any member in an animal mechanism. But I think I can 

 easily account for this mistake of Mr. L. or rather of his painter, for in the same 

 water wherein I have seen these plants and animalcula I have observed a small 

 round animal, whose numerous legs stand like radii all round its body. This 

 has a swift progressive motion, but will very often lie still (when you can only 

 perceive those radii) and then turn very swiftly round like a wheel, sometimes 

 one way, and then stop and turn the other way, without stirring a hair's breadth 

 forward. Now it is very probable that one of these might show its motions so 

 very near to, or among a tuft of the other fixed animalcula, that it might be 

 very easily mistaken for part of the same, and I am very confident this is mat- 

 ter of fact. 



These animalcula are sometimes seen loose, but generally they are fixed in 

 clusters by their tails to other bodies, and perhaps cannot separate themselves, 

 and I think it no mean instance of wisdom, that many kinds of water insects, 

 which are so fixed, and even some of which have but slow and irregular motions, 

 are furnished with such organs about their heads, the vibration of which brings a 

 constant current towards their mouths, and with that food for their support ; 

 otherwise they would be starved for want of nourishment. 



The insects on whose bodies I have seen these animalcula are of divers sorts, 

 and I have observed no small variety in the water of our ditches, not only of 

 reptiles and the caterpillar kind, but of eels and perfect shell-fish, both crusta- 



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