602 Sergius Morgulis 
What are the exact relations between the process of the formation 
of new segments and the process of the growth of those segments ? 
With these questions in mind a number of worms were divided 
into two lots. In one lot about two-thirds of the body was 
removed, while in the other lot one-third was cut off. “The worms 
were examined every four days and sometimes at intervals of 
two days. Records were kept of the number of regenerating 
segments and of the length of the tails measured by a compound 
microscope with eye-piece micrometer. 
The experiment was started on August 10, 1908, and within 
twenty-four hours after the operation the edges of the wound 
were closely drawn together, but there was as yet no trace of new 
tissue. On the second day, however, many of the worms had 
already produced new tissue. But in this respect there was an 
important difference in behavior between the worms from which 
two-thirds of the body had been removed and those from which 
only one-third had been removed. From the records made on 
August 12, it was found that 50 per cent of the former but only 
14 per cent of the latter had proliferated new material. 
At this stage one finds only a bud of undifferentiated new tissue, 
which grows out through a small foramen in the region of a coal- 
escence of the margins of the wound. ‘This bud of regenerated 
material takes on the appearance of a plug. In the course of 
the succeeding days this plug of tissue increases not only in length, 
but likewise in its circumference, producing thus a reopening 
of the margins of the wound previously drawn together. There 
is very little differentiation in the proliferated tissue, though a 
beginning of it can already be observed. In Fig. 2 are repre- 
sented a few buds found on the second day; these as arranged 
form a complete series of stages of regeneration for the first two 
days. 
At first the plug of new tissue has a perfectly round surface 
(Fig. 2, a), but then occurs an increased lateral growth (C), 
which results in the formation of two horn-like elevations. On 
the second day in some worms these elevations may become 
separated from the rest of the proliferated material by delicate 
septa (¢); ultimately they will grow into long brittle-like append- 
ages of the anal segment. 
