PROCEEDINGS OF 



THE ROYAL SOCIETY^- 



( MOV 12 1914 

 Section B. — Biological Sciences. \. , . v 



The Influence of Osmotic Pressure upon the Regeneration 



of Gunda ulvae. 



By Dorothy Jordan Lloyd, B.Sc, Bathurst Student, Newnham College, 



Cambridge. 



(Communicated by Prof. J. Stanley Gardiner, F.R.S. Eeceived March 21, — 



Read April 30, 1914.) 



CONTENTS. 



PAGE 



I. — Introduction 1 



II. — Preliminary Experiments on Reduction and Growth in Whole Animals... 3 



a. Starvation of Fully -fed Worms 3 



b. Feeding of Starved Worms 5 



IIT. — Preliminary Experiments on Duration of Life of Whole Animals in 



Solutions of Different Osmotic Pressure 5 



IV. — Study of the Normal Course of the Regeneration of the Posterior End... 6 



Y. — Eegeneration in Solutions of different Osmotic Pressure 10 



YI. — Discussion 17 



VII. — Summary 18 



I. INTRODUCTION. 



This work was carried out during the summer of 1912 and the spring of 

 1913, at the laboratory of the Marine Biological Association, at Plymouth. 

 The object of the investigation was to discover how far marine turbellarians 

 could be made to undergo variation while regenerating lost parts, and, if 

 possible, to correlate the variations with definite physical conditions. Gunda 

 ulvce was the only species used during the course of the investigation. It is 

 a small Triclad and its structure has been described in detail by Wendt(16) 

 and Iijima (5). 



VOL. LXXXVIII. — B. B 



