72 Elementary Biology. 



chlorophyll ; and thirdly, it is therefore able to integrate 

 new protoplasm from inorganic material. 



The varieties of form and life-history exemplified amongst 

 the Protophyta are very numerous. Although it is not 

 within the scope of this book to enter into a description of 

 these allied forms, yet mention must be made of the Diatom- 

 acece, of the Saccharomycetes and Schizomycetes, as examples 

 of this important group. The unicellular Diatomacece are 

 particularly remarkable for their variety of form, and for the 

 great beauty of their silicious skeletons. It is possible that 

 some of the types included under the Protophyta may re- 

 present stages in the life-history of the Metaphyta, and 

 hence ought by rights to be considered in that relation. 

 The Saccharomycetes, represented by the common Yeast - 

 plant (Toruld), are by many botanists looked upon as 

 degraded Metaphyta. For further details with regard to 

 these forms, however, reference must be made to such text- 

 books of Botany as those of Gcebel, Strasburger, De Bary, 

 and others. 



