VOL. XLIV.] PHILOSOPHICAL TRANSACTIONS. 385 



be placed right over the basis of this chalice, the appearance of the whole 8 or 

 9 branches is like that of a star with so many rays proceeding from the same 

 centre. 



When the cluster is touched, and even frequently without it, all the branches 

 fold together inwards, and then constitute a small round mass. The stem, 

 which carries all the cluster, contracts also at the same time, folding itself up 

 like a workman's measuring rule, that consists of 3 or 4 different joints. 



He saw for the first time the polypi he has been describing, on the 30th day 

 of May of the last year 1 746. They were on a water plant, which he had taken 

 from a ditch, and disposed in one of his large glasses. They immediately struck 

 him by their beauty, and he could not help being curious to know in what man- 

 ner such clusters were formed. The relation they bore to the species first above 

 described, and to some other species which he had before observed, gave him 

 reason to believe that the cluster must have sprung from a single polypus, by 

 means of several successive divisions. He was not however contented with judg- 

 ing of them from analogy only; he was desirous to be actually an eye-witness of 

 their operations ; and the observations which he therefore made on them, dis- 

 closed a new fact, which he should never have suspected, and which he could 

 never have come to the knowledge of, if he had contented himself with the 

 judgment he made of them from analogy only. 



He supposed, when he began to observe, that every cluster in question came 

 from a single small polypus, like those with which the clusters were so plentifully 

 provided. He therefore began by endeavouring to get one of these polypi single, 

 and fixed on such a body as he could well dispose in his glass, so as to keep it 

 within the reach of a magnifier of a short focus : and he pursued for this purpose 

 his ordinary method. 



He took some clusters of these polypi well advanced, he put them apart in a 

 glass filled with proper water to afford them sustenance; he put also into the 

 same glass a slip of water horsetail, after he had carefully examined it, and so 

 assured himself that there was no polypus on it. He expected that some polypi 

 would soon detach theirtselves from the clusters, and that some of those polypi 

 would fix on the horsetail, by which he should be enabled to set them apart, and 

 to observe in other glasses the progress of the clusters, which would, as he made 

 no doubt, be soon produced from them. " 



It was on the 30th of May, that he set the clusters apart in the glass. On 

 the 31st he could discover nothing new, and on the 1st of June he had no op^ 

 portunity of observing; but on the 2d in the morning he found against the sides 

 of the glass several small clusters of polypi, of the species now described. He 

 wag surprised to find them so far advanced, for they could not have begun at the 

 soonest before 10 o'clock at night, on the 30th of May. He saw on the 2d of 



VOL. IX. 3D 



