Pressure upon the Regeneration of Gunda ulvae. 



1. 100 c.c. distilled water + 50 c.c. sea-water. 2. 100 c.c. distilled water + 100 c.c. sea- 

 water. 3. 100 c.c. distilled water + 200 c.c. sea-water. 4. Sea-water. 5. 100 c.c. sea- 

 water +10 c.c. 2p[ NaCl. 



Table II. 







Time required. 





No. of 



Osmotic 















solution (see 



pressure in 





For 



Course of regeneration. 



Table I). 



atmospheres. 



For healing 

 wound. 



perforation 

 of mouth. 





4 



2-0 



Wounds never 

 close 





All pieces die under 21 days. Both 

 gonads show degeneration. G-ut 

 cells swollen and vacuolated. 



5 



3 5 



8-10 days 



Mouth never 



Testes continue functioning for 







perforates 



24 days after section, forming 









accumulations of sperm. Gut 

 cells vacuolated. Regeneration 

 never complete. 



6 



7-5 



6-10 days 



18 days • 



Testes function for 6 weeks after 









section. Disintegration of gonads 

 begins in 8 weeks. Regeneration 

 complete in 12 weeks. 



7 



11 -o 



6-8 „ 



14 „ 



Testes only function for a few days 

 after section. Gonads very re- 

 duced in 8 weeks. 



8 



15 -0 



5-7 „ 



10 „ 



Gut cells always remain normal. 

 Regeneration complete in 6 weeks. 

 Secondary sexual organs appear. 



9 



18-5 



3 „ 



8 „ 



Regeneration complete in 4-5 weeks. 

 Secondary sexual organs appear. 



10 



22 -5 



3-5 „ 



9 „ 



Regeneration complete in 7 weeks. 



(sea-water) 









No trace of generative system 

 present. 



11 



29 "5 



• 6-9 „ 



21 



Regeneration takes 8-9 weeks. 

 Genital system entirely absorbed. 



12 



33 -5 



6-10 „ 



Mouth never 



Gut cells in these tissues appear 









perforates 



shrunken, with very dense proto- 

 plasm. " Tailless " forms pro- 

 duced. 









13 



40-5 



Wounds never 

 close 





All pieces die without any regene- 

 ration in 21 days. 



