AUTHOR S ABSTRACT OF THIS PAPER ISSUED 

 BT THE BIBLIOGRAPHIC SERVICE, MAY 1 



ASEXUAL MULTIPLICATION AND REGENERATION 

 IN SAGARTIA LUCIAE VERRILL^ 



DONALD WALTON DAVIS 



FORTY-TWO FIGURES 



CONTENTS 



Introduction 162 



Description of material 163 



Fission and regeneration 167 



Plane of fission 169 



Course of regeneration 182 



Formation of new siphonoglyphs 183 



Development of new mesenteries 184 



Number and arrangement of mesenteries in regenerated regions 185 



Order of development of mesenteries 192 



Results of repeated fission and regeneration 198 



Discussiori of regeneration in hexactinians 200 



Resorption of old mesenteries 200 



Sequence of new mesenteries 201 



Siphonoglyphs and directive mesenteries 204 



Influence of old bounding mesenteries 206 



Pairing of mesenteries 207 



Orange stripes and cinclides 207 



Orange stripes in fission and regeneration 209 



External indications of internal structures 217 



Composition of natural groups 218 



Siphonoglyphs 219 



Mesenteries 220 



Orange stripes 221 



Form resulting from ontogenetic development 223 



Summary 225 



Bibliography 231 



Symbols used in tables and plates 232 



General explanation of tables 3 to 8 233 



Tables 3 to 14 234 



Plates 244 



1 Contributions from the Zoological Laboratory of the Museum of Compara- 

 tive Zoology at Harvard College, No. 318. 



161 



