CHAPTER XX. 



HETEROGENESIS IN LOWER ORGANISMS. 



Higher and Lower Organisms. Their Modes of Deatli. Matter of 

 Aquatic Lower Organisms most prone to undergo Heterogenetic 

 Changes. Dr. Pringsheim's Observations on Algse. Dr. Braxton 

 Hicks on production of AmcEbcC in Moss-radicles. Development of 

 Amoebce into Ciliata. Mr. Carter's observations on Nitella. Pro- 

 duction of Monads. M. Nicolet on Mode of Origin of Amcebse and 

 Actinophrys. Formation of Trichomonas. Its Conversion into 

 other Forms. Mr. Carter on Development of Actinophrys in 

 Spirogyra. Origin of Monads and Amoebee. Development of 

 Pythium in ' resting-spores ' of Algte and in Rotifers. Appearance 

 of Astasiae within Cells of Spirogyra. Other Heterogenetic Changes 

 in Algce and Desmids. Aut)ior's Observations on Vaucheria. 

 Mode of Origin of Amcebge and Actinophrys, Heterogenetic 

 Changes in Nitella. Embryonal Spheres. Their various Trans- 

 formations. Origin of complex egg-like Bodies. Transformations 

 of Chlorophyll Corpuscles. Analogous changes previously described. 

 Dr. Braxton Hicks on the Heterogenetic. Origin of Gloeocapsa. 

 Dr. Gros on Origin of Diatoms and Desmids. Confirmation of his 

 Views. Origin of Desmids from Chlorophyll Corpuscles. Other 

 Modes of Development of Desmids and Diatoms. Modes of Origin 

 of Euglense. Interesting Nature of these Organisms. Their various 

 Transformations. Reasons why Algse and allied Organisms give 

 birth to such varied Products. Bearing of Facts recorded upon 

 Zoological and Botanical Classifications. 



WE pass now to a consideration of the hetero- 

 genetic processes which occur in much lower 

 forms of life. And it should be borne in mind when 

 studying the changes that take place in the proto- 



VOL. IT. B b 



