TABLE OF CONTENTS 
PART 1]. 
STATEMENT OF THE WORKING HYPOTHESIS 
CHAPTER 
XIII. 
XIV. 
XV. 
XVI. 
INTRODUCTION, 
- THE SCOPE AND LIMITATIONS OF COMPARATIVE MORPHOLOGY, 
. THE LIFE-HISTORY OF A FERN, 
. ON THE BALANCE OF THE ALTERNATING GENERATIONS OF 
ARCHEGONIATAE, 
. CYTOLOGICAL DISTINCTION OF THE ALTERNATING GENERATIONS 
OF ARCHEGONIATAE, - 
. ALTERNATION IN THALLOPHVTES, 
. BIOLOGICAL ASPECT OF ALTERNATION, 
. STERILISATION, - 
. THE SPORANGIUM DEFINED, 
. SOME GENERAL ASPECTS OF THE POLYSPORANGIATE STATE, 
. VARIATIONS IN NUMBER OF SPORANGIA, 
. THEORY OF THE STROBILUS, 
. SPORANGIOPHORES AND SPOROPHYLLS, 
ON THE RELATIONS BETWEEN THE STERILE AND FERTILE REGIONS 
IN THE SPOROPHYTE, 
EMBRYOLOGY AND THE THEORY OF RECAPITULATION, - 
ANATOMICAL EVIDENCE, 
SYMMETRY OF THE SPOROPHYTE, 
PAGE 
103 
113 
119 
132 
144 
156 
173 
188 
201 
