LARVAL STAGES OF SCHLOENBACHIA. 



JAMES PERRIN SMITH. 



Stanford University, California. 



CONTENTS. 



PAGE 



Introduction 237 



Law of Acceleration of Development 237 



Paleontogeny 238 



Life History of Cephalopods 239 



Palingenesis 240 



Omission of Stages 241 



Method of Phylogenic Research 243 



Nomenclature of Stages of Growth 244 



Genus Schloetibachia Neumayr 245 



Schloefibachia oregotiensis 246 



Ontoge.nic Stages 248 



Nepionic or Larval 248 



Phylembryonic 248 



Ananepionic 249 



Metanepionic 249 



/ Glyphioceras Stage 250 



Paranepionic \ Gastrioceras Stage 251 



' Paralegoceras Stage 251 



Neanic or Adolescent 252 



Ananeanic 252 



Metaneanic 253 



Paraneanic 253 



Table of Stages of Growth 254 



Cross-Sections 256 



Ephebic or Adult 257 



Synopsis of Results . 2 



57 



Plates A, B, C, D, E 260-268 



Introduction. 



Law of acceleration of development, — A few years ago natural- 

 ists were very much given to speculating about the theory of 

 evolution, reasoning abstractly for or against it, and construct- 



237 



