436 M. Eckhard on the Organization 



the fact that such phenomena cannot be produced, but depend 

 upon fortunate circumstances, which we must take the chance of 

 meeting with. Lastly, should the observation of Werneck*, who 

 saw a Peridinium inside a Navicula and thought that it had been 

 eaten by it, be true, as can scarcely be doubted from so acute an 

 observer, the dispute regarding the nature of the Bacillarina would 

 be at an end. 



III. Volvocina. — How Siebold has been able to refer these to 

 the vegetable kingdom is to me incomprehensible ; the distinct 

 ascent and descent of Volvox globator, when kept in glasses, the 

 spontaneous motion of the two proboscides of each separate ani- 

 malcule, and the contractile vesicle discovered by Ehrenberg, 

 leave no further doubt on this matter. 



It still remains for us to bring forward and examine the 

 grounds upon which Siebold based his opinion on the nature 

 of the three families we have mentioned. At pages 8 and 9 we 

 find the following remarks, which, if they cannot together be ad- 

 duced as a direct ground for the author's view, nevertheless may 

 serve as matter for further consideration : — 



1) "It is quite different with the locomotions of the lowest 

 vegetable organisms (among which, as we know, the families 

 above-mentioned are enumerated), since these are not the conse- 

 quence of an internal voluntary influence, and do not arise from 

 any spontaneously contractile and expansible parenchyma," &c. 

 It appears to me to follow with certainty from the observations 

 detailed in I. to III., that the motions are truly dependent upon 

 an internal voluntary influence of these animals. But as regards 

 the supposition that they do not arise from any spontaneously 

 contractile and expansible parenchyma, this is not proved. As 

 the body of the Bacillarina, which is almost as transparent as 

 water, is inclosed by a siliceous carapace, it is hardly possible, 

 with our present optical resources and the ordinary methods of 

 optical investigation, to observe the contraction of the body. Be- 

 sides, the organs regarded by Ehrenberg as ovaries often exhibit 

 such different arrangements, that we are easily led to imagine 

 the existence of an expansibility and contractility of the paren- 

 chyma of the body. 



2) " Ciliated organs occur in the vegetable kingdom in the 

 form of ciliated epithelium in the spores of Vaucheria, and in the 

 form of isolated, long whip-shaped threads in the spores and early 

 stages of different Conferva?, among which we find several of the 

 organisms described by Ehrenberg as Monadina and Volvocina" 

 Siebold was evidently led to this assertion by a contribution 

 of Thuret to the ' Annales des Sciences Naturelles/ which work 



• Monthly Report of the Berlin Academy, 1841, p. 109. 



