PREFACE TO THE SECOND EDITION 



Since the first edition of the present work was pub- 

 lished, the number of important investigations on the struc- 

 ture and development of the Archegoniatse has been so 

 great that it has been found necessary to recast entirely 

 certain portions of the work, this being especially the case 

 with the chapters dealing with the eusporangiate Ferns. 

 The whole book, however, has been carefully revised, and a 

 good deal of new matter introduced, including two special 

 chapters on the geological history of the Archegoniates, 

 and the significance of the alternation of generations. 



Some of the new material incorporated in the present 

 work is published for the first time; but much of it is based 

 upon papers published by the writer since the first edition 

 was published. The work of other investigators has been 

 freely drawn upon, and acknowledgment has been made in 

 all cases where statements or illustrations have been bor- 

 rowed from other sources than the writer's own inves- 

 tigations. 



The large number of recent books and papers on the 

 Archegoniates has involved an entire revision of the bibli- 

 ography, which has been materially augmented. It is 

 hoped that it will be found to be a fairly complete list of 

 the more recent works bearing upon the structure of the 

 Archegoniates. 



The results of more recent investigations have necessi- 

 tated, in some cases, a modification of certain views ex- 

 pressed by the author in the earlier edition. In other 

 cases, however, his views have been confirmed as the result 

 of more complete knowledge of certain forms. 



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