CONTENTS 



Page 



Introduction 1 



Type genus 2 



Acknowledgments 3 



External morphology 4 



Size 4 



Commissure 4 



Plication 6 



Costation 7 



Stolidium 8 



Delthyrium and deltidial plates 13 



Internal morphology 14 



Camarophorium 14 



Spondylium 16 



Musculature 18 



Hinge plate and cardinal process 22 



Crura 22 



Lophophore 23 



Pallial markings 23 



Shell structure 25 



Life habits 26 



Phylogeny 29 



Classification 33 



Key 35 



Systematics of superfamily Stenoscismatacea 37 



Family Atriboniidae 37 



Subfamily Atriboniinae 37 



Subfamily Psilocamarinae 77 



Family Stenoscismatidae 95 



Subfamily Stenoscismatinae 95 



Subfamily Torynechinae 152 



Species doubtfully Stenoscismatacean 160 



Genera no longer included in Stenoscismatacea 162 



References cited 166 



Explanations of plates 175 



Index 187 



