In spite of the vigilance and wise counsel of many friends numerous blemishes remain and for these the author is alone responsible. A. C. SEWARD. +Downing College Lodge+, _February 10, 1917_. * * * * * +Note.+ The letters A and B added to references in the footnotes indicate that the works will be found in the Bibliographies at the end of Volumes I and II. TABLE OF CONTENTS CHAPTER XXVIII CYCADALES (Recent). Pp. 1–34. CHAPTER XXIX PTERIDOSPERMEAE (continued from Volume II). Pp. 35–85. PAGE I. =LYGINOPTERIDEAE= 35–85 =Lyginopteris= 35–70 _Telangium_ 54, 55; _Lagenostoma_ 55–64; _Lagenospermum_ 64–66; _Pterispermostrobus_ 66, 67. =Heterangium= 70–85 _Sphaerostoma_ 78–81. CHAPTER XXX II. =MEDULLOSEAE= 86–165 i. _Medullosa_ 86–109, 156–163 _Myeloxylon_ 106–110; _Neuropteris_ 110–117; _Alethopteris_ and _Linopteris_ 113; _Trigonocarpus_ 117–124; _Codonotheca_ 124–126; _Schützia_ 126–128; _Whittleseya_ 128–131; _Dolerophyllum_ 132–139; _Ottokaria_ 139–141; _Strobilites_ 141, 142. ii. =Colpoxylon= 142–145 iii. =Rhexoxylon= 146–149 iv. =Sutcliffia= 149–156 _General considerations suggested by the anatomical features of Medullosa_ 156–163 II. =A. STELOXYLEAE= 163–165 =Steloxylon= 163–165 CHAPTER XXXI PTERIDOSPERMEAE. (Foliage and seeds.) Pp. 166–174. _Pecopteris Pluckeneti_ 166–168; _Eremopteris artemisaefolia_ 169–172; =Wardia= 172, 173; _Adiantites bellidulus_ and _Lagenospermum Arberi_ 173, 174. CHAPTER XXXII CYCADOFILICES. Pp. 175–213. I. =MEGALOXYLEAE= 175–180 =Megaloxylon= 175–180 II. =RHETINANGIEAE= 181–183 =Rhetinangium= 181–183 III. =STENOMYELEAE= 183–185 =Stenomyelon= 183–185