598 Sergius Morgults 
numbers are rather small and the segments can be easily counted 
owing to their large size and to the presence of parapodia. In 
the experiments to be described in the following paragraphs a 
complete record has been kept, with the object in view of deter- 
mining in what relation the regenerated segments stand to the 
old and to the removed segments. 
A number of worms were divided into three groups. In the 
first group (A), containing 23 worms, 471 segments in all were 
removed; that gives an average of about 21 segments (20.5) 
to each individual worm. ‘The total number of segments left 
over in the old pieces of the worms amounted to 381, or an average 
of about 17 segments (16.6). Thus in the first group on the 
average a little over one-half of the worm’s body was cut off. 
In a second group (B), containing 19 worms, 273 segments were 
removed, or on the average about fourteen (14.4), while the 
number of segments in the pieces experimented on was 441, or 
an average of about twenty-three (23.2). Thus, in this group a 
little over one-third of the worm was cut off. Lastly, in the 
third group (C), containing 14 worms, where only 111 segments 
were removed (8 on the average), and 425 (or about 30 for each 
piece) were retained, only about one-fourth of the worm was 
taken off. 
The worms were kept in pure sea-water, in-which there was 
no food present. 
In Table I are given the average numbers of old segments and 
removed segments as well as of segments regenerated in the course 
of two weeks, likewise the corresponding data for each individual 
worm. | 
From this table we learn that 155 segments (an averageof 6.8) 
have been regenerated from the pieces of worms of the first group; 
120 segments (an average of 6.3) from those of the second group; 
and 68 (4.9 on the average) from pieces of the third group. These 
facts are expressed graphically in the diagram shown in Fig. 1. 
The ratio between regenerated and the original anterior seg- 
ments expressed in percentages is 40.7 for Group A, 27.2 for 
Group B, and 16 for Group C. The ratio between the number 
of regenerated segments and of those removed expressed in per- 
