46 Dr. F. von Wagner on 



Leuckart*, but has not since been investigated again, seems 

 to a certain extent to present the appearance of gemmation ; 

 yet when considered in connexion with similar processes in 

 the forms most closely allied {Autolytus cornutus and the true 

 Syllidse) it v/ill certainly require another interpretation. 

 Indeed it has been stated by Ehlers precisely with regard to 

 the asexual reproduction of the Syllidae (including Autolytus) 

 " that there is here no question of fundamental differences, 

 but that there merely takes place a development of the same 

 process differing in degree " f. As a matter of fact we ought 

 certainly not to perceive gemmation in the asexual reproduc- 

 tion of Autolytus proUfeVj but merely an extreme one-sided 

 development of the usual simpler mode of reproduction of the 

 segmented worms. 



It is evident from what has been stated that the asexual 

 multiplication of Microstoma, which has the chief claim upon 

 our attention in the present investigation, represents fission. 

 That which was demonstrated by Glaus and Goette for the 

 formation of Ephyrae is perfectly applicable in all essential 

 points to the fission of the Microstomids also, and it is suffi- 

 cient to refer the reader to what has been quoted above from 

 the writings of the investigators in question. 



Since all forms of reproduction which have been regarded 

 as instances of terminal gemmation thus prove to be cases of 

 fission, we arrive at the result that a formation of terminal 

 buds in the customary sense has no existence whatever. 



IV. 



I have yet to allude to the statements of earlier investi- 

 gators. 



If we may neglect the more incidental assertions of older 

 authors, E. Hseckel was the first who, although a long time 

 ago, attempted systematically to establish the theory of fission 

 and gemmation. In his classic ' Generelle Morphologic,' so 

 rich in fresh points of view, this investigator wrote (1866) : 

 " In self-fission the growth of the individual which ushers in 

 reproduction is total, and in the act of fission is destroyed in 

 its totality, so that the products of fission are equivalent to 

 one another. In the formation of buds, on the contrary, it is 

 an isolated portion of the body of the individual which, by 

 means of special growth, leads to the formation of a new indi- 



* H. Frev and R. I^euckart, " Beitrage zur Kenntniss wirbelloser 

 Thiere &c.,' Braunschweig, 1847, pp. 91 et son. 

 t E. Ehlers, op. cit. p. 208. 



