NATURAL HISTORY OF THE STAR-FISH. 
219 
On September 26 five of the larger stars in the original car were deprived 
of the arm opposite the “eye,” or madreporic plate, and then placed in a car with 
barnacles for food. The subsequent measurements show that they kept on eating 
and growing at about the usual rate, like the specimen similarly treated in the last 
experiment described. The measurements are given in tabulated form below, the first 
measurement indicating the length of the longest arm. 
Sept. 26. 
Oct. 12. 
Oct. 25. 
Koi 
-. 5. 
Nov 
. 21. • 
Specimens. 
Longest 
arm. 
New 
growth. 
Longest 
arm. 
New 
growth. 
Longest 
arm . 
New 
growth. 
Longest 
arm. 
New 
growth. 
Longest 
arm. 
New 
growth. 
A 
32 
0 
30 
3 
42 
7 
41 
it 
40 
12 
li 
30 
0 
35 
3 
38 
7 
41 
12 
40 
11 
C 
28 
0 
30 
3 
35 
7 
38 
10 
38 
12 
D 
27 
0 
29 
3 
30 
6 
35 
9 
38 
11 
E 
25 
0 
28 
3 
34 
7 
35 
9 
A comparison of the table with that on page 217 shows that these stars which are 
regenerating an arm grew at about the same rate as the complete stars during the 
same period. The rate of regeneration was also about the same as the rate of grow th 
in the original arms, except that toward the last the new members grew in some cases 
somewhat more rapidly. 
Another experiment was made similar to the above, except that two arms were 
taken off instead of only one, and the stars were younger at the beginning. The stars 
were at first all about 12 mm. The eight detached arms were put in the car also, and 
on September 10, 26 days after they were detached, five were still alive and apparently 
in good health, but had neither grown nor shown any sign of regeneration. One is 
figured natural size in fig. 24 b. 
The growth of these specimens is tabulated below. (Measurements were made 
from mouth to tip of new arm, but figures in table indicate merely new growth, and 
are derived by subtracting 3 mm. from original figures.) 
1 It was intended at first to keep account only of rate of regeneration, and so four stars were picked out, of 
about the same size, and one only was measured. This was 12 mm. The others may have been 1 or 2 mm. larger 
or smaller. The growth of this specimen and the size of the single arm alone, on September 26, are given in 
diagram, fig. 24, a and b respectively. 
2 One detached arm, still alive, measures 7 mm. 
3 Tips cut off and arms slit on September 15. The longest arm was then 22 mm., and the regenerating arms 
15 and 10 mm., respectively. 
4 Arm broken off, probably by handling, on September 5. 
This experiment shows conclusively that when even two arms are lost the growth 
of the star-fish is not necessarily arrested or the rate of growth diminished. The rate 
of growth in the new arms was greater than in the original arms, and there was a 
tendency, therefore, for all to become ultimately of the same length. 
