156 Proceedings of Learned Societies. 



where, speaking of the rarity of the occurrence of fissiparous gene- 

 ration in Actiniaria, he states that he had never seen it occur spon- 

 taneously himself, but quotes the following observation of a friend : 

 — " An Anthea cereus, which had been in captivity thirteen days, 

 devoured with great relish a dead shellfish. I watched the opera- 

 tion of seizing and swallowing, and there was nothing remarkable 

 in the appearance of the Anthea on Monday. On Tuesday morning, 

 going to look at my prisoner, I observed the rejected shell at the 

 bottom of the jar, and, to my great puzzlement, instead of one 

 Anthea there were two, of nearly .equal size, but smaller than my 

 old friend. Both appeared languid, and from the margin of one 

 two tentacua appeared sprouting ; they hung in so very flaccid a state 

 that I could not examine the mouth yesterday, but to-day one ex- 

 poses a mouth fully formed." We have little else recorded here 

 than the fact of the division and its extreme rapidity. There can 

 be little doubt that in this case, as in Dr. Bennett's, the division 

 was effected by muscular action. Nearly a century ago Decquemare 

 observed that several Actinia? could be divided artificially in almost 

 any way, the several parts being capable of forming independent 

 animals. Sir J. Dalyell has recorded a mode of reproduction 

 in one species — Actinias lacerata — accomplished, apparently, by 

 muscular action. He describes, in this species, the outline 

 of the base becoming sinuous, and the prominences gradually, 

 in the course of a week or two, becoming pinched off, main- 

 taining their connection only by a veiy slender lengthened 

 filament, not in contact with the glass, but free above it. 

 Rupture of the connecting thread at length takes place, and the 

 independent fragment becomes developed into a perfect anemone. 

 He says of the process : — " It is not quite obvious how the pro- 

 longation is effected, unless by contraction of the basis and reces- 

 sion." All authorities agree in stating that fissiparous generation 

 occurs either in the way described by Dalyell — by separation of a 

 part of the margin of the base, or by division from above down- 

 wards, not from below upwards, as I have described. Milne 

 Edwards says : — " Spontaneous fissiparous generation occurs either 

 by detachment of fragments from the inferior border of the body, 

 which, continuing to live, become developed into perfect animals, 

 or at other times division commences by a narrowing or strangula- 

 tion (etranglemenf) of the superior extremity of the body, which, 

 becoming more and more pronounced, causes a bifurcation, the 

 branches of which complete themselves each on its own side, so as 

 to constitute two distinct individuals. These may remain united by 

 the base, and so cause an aggregation of polypes, or may be sepa- 

 rated completely." Dalyell is the only authority who attributes 

 the separation of the fragments, in any case, to muscular action. 

 How the process is effected when it occurs in the more common way 

 — from above downwards — is difficult to imagine, unless it be similar 

 to ulceration in higher animals, or due to muscular action. Gosse 

 evidently attributes it to a process of growth. He says : — " The 

 greater part of the Astrasacea increase by disc buds and spontaneous 

 subdivision, the disc of the polype gradually widening by growth, 



