AMONG SIMPLE 8ARC0DE Ofl&ANISMS, 437 



from tlieir surface small, blunt, irregular, pseudopodial projections. 

 These gradually become more pointed, thinner, and longer ; their 

 motions become more lively, and the amoeboid pseudopodia pass 

 into vibratile cilia. 



The change of pseudopodia into vibratile cilia had been already 

 shown by Haeckel* to occur in other instances, and has been re- 

 garded by him as proving the identity of amoeboid protoplasm- 

 motion with ciliary motion. I am enabled to bring forward a 

 confirmation of this view in the apparent passing of pseudopodia 

 into cilia on the gastric surface of Myriothelaf. 



The spherical cell-heap whose surface has in this way clothed 

 itself with vibratile cilia begins by the aid of these to rotate slowly 

 within the egg-membrane. This is at last ruptured, and the 

 ciliated sphere escapes and swims about by means of its cilia in 

 the surrounding water (E). 



The Magosphcera is now in the condition of a multicellular 

 ciliated sphere so closely resembling one of Ehrenberg's Volvo- 

 cinece, that if its history were not known it would, without hesi- 

 tation, be placed in this group as a genus closely allied to if not 

 identical with the Synura of Ehrenberg. 



The cells, which have a spherical form, or are more or less poly- 

 hedral from mutual pressure, now become regularly pyriform, and 

 are seen to be united in the centre of the sphere by their elongated 

 ends (F), while the peripheral end is rounded off and furnished with 

 cilia, which appear to sit upon the margin of this end in a circle 

 interrupted at one side by a spiral arrangement, as in the peri- 

 stome of Vorticella, &c. 



The cells have no membrane, and the intervals between them 

 are filled with a watery, structureless, jelly-like secretion from 

 their surface, as in the Volvocinece. Every cell encloses in its 

 protoplasm a nucleolated nucleus surrounded by granules, and 

 possesses also a contractile vesicle. 



After the MagospTicera has thus continued for some time swim- 

 ming about in the sea as a ciliated sphere, it begins to resolve 

 itself into its constituent elements. The single ciliated cells now 

 separate from one another and swim about independently (G). In 

 this state they might be easily taken for peritrichal ciliate In- 

 fusoria, or for isolated cilia-cells of the epithelium of the higher 

 animals. These separate cells are very contractile, and are con- 



* Beitrage zur Plastidentheorie. 



t " On tbe Structure and Derelopment of Myriothela," Phil. Trans. 1875. 



