﻿Feb., 1858.] 



ELLIOTT SOCIETY. 



277 



very small in proportion to the original polyp. I have never seen 

 the plane of constriction or fission pass through the axis of the 

 body, but altvays on one side of it. Yesterday, (15th ult.) ob- 

 served that, as I had surmised, the central or ovarian chamber, 

 has its transverse axis elongated in the same direction as the 

 base before division. 



It must be borne in mind however, that in no instance 

 have I seen two individuals actually formed by separation. 

 Though the process has been going on ever since the 13th ult., 

 having begun, indeed, on the 12th, in the specimen first noticed, 

 it is not yet complete. Nevertheless, in that specimen, the two 

 parts of the base have become very distinctly separated, and the 

 appearance of separation into two parts is very distinctly exhibited 

 in the tentacular crown. 



Jan. 18th. — In the oldest case of fission observed, the formation 

 of two perfect bases had so far progressed that the centres of 

 radiation for each of them, which had hitherto been excentric, in 

 relation to the circular outline, had now become central for each 

 of the partial bases. At my last observation, these two centres 

 of radiation were decidedly out of the centres of their respective 

 circular bases, being the result of the division into two of the 

 centre of radiation of the base of the original polyp. 



Jan. 30. — My young Actinia cavernosa, first mentioned as under- 

 going spontaneous fission, has apparently occupied all this time in 

 forming two new bases. The centres of radiation are now, also, 

 the centres of the circular bases; still the process of fission does 

 not seem to be complete — two scar-like seams still stretching from 

 base to base. 



Not long after the dates of these extracts, the young Actinias 

 died — ivithout completing the process of division into two. From 

 time to time I occasionally saw two small specimens near each 

 other, as if they had but lately broken apart, but I never had the 

 good fortune to observe the actual separation of two individuals. 



Actinias have been known to multiply themselves by buds, but 

 I am not aware that spontaneous fission has ever been observed 

 among them. Though these observations are incomplete, they 

 tend to show that Actinia does not represent a stage of Polypi 

 younger than that in which fissiparition begins — but since this in- 

 complete fission is exhibited only in the younger stages of this 

 Actinia, it appears more probable that the Actinidas are the highest 



