396 Dr. C. F. Liitken on Spontaneous 



trace in those cases in which small portions of the margin of 

 the pedal disk of the Actinias spontaneously, accidentally, or 

 artificially detached acquire an independent life and become 

 developed into Actinias (A. lacerata, diantJius). Spontaneous 

 transverse scissiparity is known only in Gonactinia (prolvfera) ; 

 and even this has much more the character of a gemmation. 



The faculty of regeneration is likewise highly developed in 

 the Fungiae ; and in consequence of injuries it often happens 

 that an individual splits into two or more, or that a larger or 

 smaller number of buds are produced ; for in these normally 

 simple Anthozoa gemmation is not a normal phenomenon, and 

 it is not always possible to trace a precise boundary between 

 gemmation and the regeneration which takes place after an 

 injury. What has been described in Diaseris as a union of 

 several sectors originally separate is rather a spontaneous or 

 semispontaneous division, followed by phenomena of regenera- 

 tion and gemmation. 



Although an important part has been ascribed to spontaneous 

 division in the compound Madreporaria, and it has even been 

 supposed that this mode of multiplication characterizes certain 

 systematic groups, I have become convinced that its importance 

 in this respect is completely illusory, and that it will be found, 

 by a more careful examination, that in most cases (e. g. the 

 Mazandrince) this supposed division is only a gemmation. 

 As my master, Prof. Steenstrup, pointed out to me many years 

 ago, the new individual always originates as an isolated bud ; 

 but as it grows, the boundary between it and its nearest neigh- 

 bour, which must be regarded as its nurse, is seen gradually 

 to be effaced. This is precisely the opposite of what has been 

 supposed. The individuals (e. g. in the Euphyllice, the Musso?., 

 and the Symphyllice) begin by being isolated, and finish by 

 being more or less completely fused into one another. I think, 

 therefore, that the interpretation of these facts given by Mr. 

 Dana approaches nearer to the truth than that of M. Milne- 

 Edwards ; and I must maintain that (leaving out of considera- 

 tion the intercalicinal gemmation, which it would be very 

 difficult to distinguish from division) no true spontaneous 

 division has yet been ascertained to occur in the compound 

 Madreporaria. 



The result of the investigations and considerations which 

 have been set forth here, partly in extenso and partly in 

 the form of a summary, is as follows : — 



If there are many cases in which spontaneous division is 

 only a more or less disguised gemmation, and in which we are 

 not yet in a position to separate clearly one from the other, 



