THE REGENERATION OF THE TAIL IN 

 LUMBRICULUS. 



HARRIET RANDOLPH. 



CONTENTS. 

 Part I. 



PAGE 



I. Introduction 317 



Part II. 



II. General history of division 321 



III. Formation of embryonic tissue . 322 



1. Ectoderm and entoderm ........ 322 



2. Mesoderm . 323 



IV, Differentiation of regenerated tissue 326 



1. Ectoderm 326 



2. Mesoderm . . . . ■ . . . . . . , 327 



Part III. 



V. Regeneration and agamic reproduction ...... 329 



VI. Relation of the observations of regeneration in Lumbriculus to the 



germ-layer theory . ......... 331 



VII. Peritoneum and neoblasts 333 



PART I. 

 I, Introduction. 



The following paper is offered as a contribution to our knowl- 

 edge of the regeneration of lost parts, and contains more espe- 

 cially the results of an attempt to discover the precise origin of 

 the histological elements. 



Although the regeneration of lost parts has long been known,^ 

 in so far as its broader features are concerned, it is only within 



^ For an extended account of the early observers and their work, see Milne- 

 Edwards (15) and Fraisse (7), where the bibliography of the subject can be found. 



317 



