470 THE BEGINNINGS OF LIFE. 



or filaments ^ This mode of origin was distinctly 

 indicated by Dr. Gros in reference to the changes that 

 might occur in the leaves of aquatic plants. He 

 said 2; — ^ Les cellules des feuilles laissent leur vesiculines 

 chlorophylliennes se faner, ou bien elles poussent un 

 utricule hile qui s'elabore en Vorticelles, de forme 

 diverse, selon la quantite de matiere et la qualite des 

 vesicules.' Repeated observations on Vaucheria, as well 

 as other Algse and aquatic plants, have led me to believe 

 that this is one of the most frequent modes of origin 

 of the VorticelliK which are constantly found upon their 

 surface; whilst, according to M. Nicolet ^, Vorticell^ 

 may be produced upon the filaments of Nitella in an 

 almost similar manner. On other occasions Vorticellas 

 have been seen to develop from an internal bud (which 

 appears after the manner of a nucleus) within the clear 

 anterior extremity of Chlamydococcus corpuscles. This 

 mode of origin has been seen by Mr. T. C. Hildgard, 

 who says: — 'This parasite is a perfectly colourless 

 globule, apparent in the clear navel-point of the cell, 

 and exhibits a faintly opalescent hue. As it grows, the 

 cell which harbours the " incubus " loses its own indi- 

 vidual vitality.' Its external coat hardens_, but its 

 internal contents gradually disappear, as the embryo 

 ' grows and occupies more space, executing tremulous 



^ Just as in other cases vesicles are produced which become converted 

 into Desmids or Diatoms, or whose contents become resolved into 

 algoid elements (see pp. 418, 419). 



2 Loc. cit., p. 448. « See p. 478. 



