﻿Feb, 1858.] 



ELLIOTT SOCIETY. 



275 



Instance of incomplete longitudinal Fission in Actinia cavernosa 

 Bosc. By John McCrady. 

 I will present what I have to say on this subject by extracts 

 from my private journal as follows: 



Jan. 13th, 1858 — Saturday last, (9th ult.) I collected, on Sulli- 

 van's Island, some young specimens of Actinia cavernosa Bosc; I 

 think them not more than six months old. They are of a rich 

 green, lighter than that of the adult, with amber-colored tentacula, 

 smooth exterior, and semi-transparent parieties ; in the smaller 

 specimens, the tentacula are sprinkled with white. Yesterday, I 

 observed that the base of one of these smaller specimens, which 

 had climbed near the top of the jar, had assumed a dumb-bell like 

 outline, and to-day I find that spontaneous fission has proceeded so 

 far longitudinally that two distinct individuals are nearly formed; 

 the cavities of their bodies being still in communication, by means 

 of extensions of the walls of the body, which though very much 

 strained, have not yet parted; thus forming a kind of tube, which, 

 however, appears to be open below by a slit extending from centre 

 to centre of the two' partial bases thus formed. The tentacular 

 circle, and its area, were, also, divided into two tufts, one of which 

 was larger than the other. I could not discover whether the smaller 

 of these had, or did not have, a mouth. But the bases of the two 

 separating individuals already begun to assume the circumscribed 

 circular outline. The separation of the parts of the base appears 

 almost complete, while that of the parts of the tentacular crown is 

 only indicated. This shows that the fission, in all probability, 

 begins at the base. 



Jan. 14th. — To-day, the parts of the base were less strained apart 

 the connecting bands had disappeared, but the two partial bases 



