78 PHILOSOPHICAL TRANSACTIONS. [aNNO 1744. 



operation are thus completed; we see on one pedicle two polypi, joined to its 

 extremity by their posterior ends, and that show themselves on the sides of each 

 other, as in fig. 2. Where the ordinary proportion between the length of the 

 body of one of these polypi and the length of their pedicle, is pretty exactly ob- 

 served. Soon after the separation is completed, each of the new polypi begins to 

 show a pedicle of its own. And each of the new polypi has, the day after their 

 separation, a pedicle of a tolerable length ; and these new pedicles united at the 

 extremity of the first pedicle, as the branches of a tree unite at its trunk. Several 

 of the polypi have multiplied at the latest 24 hours after their first separation. 

 The new cluster has then consisted of 4 polypi, each of which had its own pedicle; 

 as every one has also had, that was afterwards produced by a new separation. 



Fig. 3 represents a cluster of 8 polypi ; and by this figure it may be apprehended 

 in what manner the pedicles of the polypi become disposed, as their numbers in- 

 crease. These several pedicles become so many branches of the cluster or sprig. 

 This figure particularly represents a cluster, whose progress M. T. followed in the 

 month of September last, 1744. It consisted, on the Qth day of that month, of 

 only one single polypus, which was placed as at b : this polypus divided itself that 

 evening, and at half an hour after 8 o'clock, there were to be discovered at b two 

 perfect polypi, whose pedicles or branches, bd, bd, continued lengthening till the 

 morning of the next day, being the 1 0th of the same month of September: at 

 about a quarter after Q that morning, these two polypi, which were then at d, d, 

 began also each to divide ; so that at a quarter past 1 1 , there were at d and d 4 

 complete polypi, whose several pedicles di, di, di, di, formed themselves soon after. 

 On the 1 1 th of the same September, about half an hour after 7 in the morning, 

 these last 4 polypi had already again divided themselves ; that is, that there were 

 at i, i, i, i, 8 distinct polypi ; and this cluster, so consisting of 8 polypi, is here re- 

 presented as it appeared on the 1 2th of the same month, between 1 and 1 1 in 

 the forenoon. The polypi are not always ranged as they are disposed in this figure, 

 for it often happens, that the pedicles and the polypi are behind each other, so 

 as to form a groupe, in which some of the polypi may chance to be hidden or 

 covered by others, either entirely or in part. This figure represents the polypi 

 and pedicles as magnified to the same degree as those already exhibited in the 

 fornier figures. 



M. T. has taken notice of clusters, the numbers of whose polypi have con- 

 stantly gone on doubling, from 2 to 4, from 4 to 8, from 8 to l6, from l6 to 

 32 : after which he has no longer been able to count exactly the number of the 

 polypi. Indeed the number is prodigious of those that are sometimes found in the 

 water, thus multiplied. He had large glasses in which they had exceedingly mul- 

 tiplied ; there was particularly, in one of them, a cluster composed of several less 

 united clusters, which is above an inch over every way. There detach themselves 



