634 Sergius Morgults 
This subject was taken up again in my work during the summer 
of 1908. Upon diluting sea-water to 75 per cent of its original 
strength I obtained invariably a distinct retardation of the rate 
of regeneration. ‘The effect made itself manifest not only in the 
smaller number of regenerating segments, but likewise in a dimi- 
nution in length of the regenerated tails. It will be seen from 
the Table XXVIII that the number of regenerated segments 
varied from 2 to 5, two and three segments being the most common 
numbers. 
TABLE XXVIII 
SEPTEMBER § TO SEPTEMBER 15 (’08) | NUMBER OF SEGMENTS 
18 
5 
| 
17 
4 
16 =) 18 18 16 
3|3)3| 3] 4 
16 
4 
Pe 
as 3 
Sea-water—75 parts. f Old | 18 1a 19 
Dist. water—z5. parts. eal 2 2 2 
15 
3 
17) 
4 
17 
5 
} 
It should be mentioned, however, that of all the experiments 
with sea-water diluted to 75 per cent this shows less of the dele- 
terious influence upon the formation of new segments than any 
other; it is used here because it belongs to the series of experiments 
the data of which are taken as a basis for this chapter. 
In the control experiment (Table XXIX) the number of regen- 
erated segments varied from 3 to 5, but, as has been said above, 
the tails were much larger. 
TABLE XXIX 
| 
SKPTEMBER § TO SEPTEMBER I5 (1908) NUMBER OF SEGMENTS 
Old | 15 | 15 | 16 18 | 17 | 17 | 20 | 16 | 19 
Wontrola(Geaawater) sete seeiiateteyecrterleieletesereets | 
saree) (ser aaa) alate 
In sea-water of strength greater than 75 per cent, as for instance 
sea-water diluted to 80, 85, go or 95 per cent its original strength 
there was exerted upon the regenerating worms neither a retarding | 
nor an accelerating influence. As will be seen from Tables XXX 
and XXXI, there is practically no difference between the worms 
of the control and the experiment so far as the rate of regeneration 
is concerned. 
