10 



Miss D. J. Lloyd. Influence of Osmotic 



Fig. 8. 



Median longitudinal sections through worm regenerating in sea-water. — 1. 7 days. 

 2. 14 days. 3. 21 days. 4. 56 days. 

 Median longitudinal sections through worm regenerating in 100 c.c. sea-water + 20 c.c. 

 2JM NaCl. — 5. 7 days. 6. 14 days. 7. 21 days. 8. 31 days. 



V. Regeneration under Varying Conditions of Osmotic Pressure. 



A number of experiments in regeneration were set up in artificial solutions 

 4-11 of Table II, in order to see what effect was produced by raising or 

 lowering the osmotic pressure of the medium. It can be seen that a range 

 of pressure of from 2 to 40 atmospheres was examined. The results of such 

 experiments show that moving the osmotic pressure in either direction from 

 a definite optimum value just below that of sea-water results in a decrease in 

 the rate of regeneration. This decrease of rate culminates, at 2 and 

 40 atmospheres respectively, in complete inhibition of the restorative 

 processes. Tig. 9 shows a number of worms on the 42nd day of regeneration, 

 which have been taken from different experimental media. 



