184 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Series C. 
Naked. 
In these experiments, glaucothoe were reared without any covering 
for the body. Five experiments, using 1*23 larvae; 50 of which 
attained the moult to the sixth stage. No mid-period examination. 
7 glaucothoe 14 percent remained in stage 4 days. 
tt It 5 tt 
It It 0 it 
tt a 7 tt 
It It g It 
The curve that may be constructed (pi. 7, fig. 33, continuous line) 
has the same range as the curve for the experiments of series A, 
but its mode is on the sixth day and the seventh day percentage is 
high, giving it a very different shape from the curves for either A 
or B. It may be objected that the absence of a mid-period exami¬ 
nation is responsible in large measure for this difference in shape. 
But the mid-period moults, if not separately recorded, will merely 
increase the record for the following morning and if the curve for 
A be plotted with the mid-period moults thus added to the day 
records (dotted line), it does not at all resemble the curve for the 
present series. So although the sixth and seventh day percent¬ 
ages may readily be somewhat higher than they would have been 
with a mid-period count, the difference would be insufiicient to 
modify the curve essentially. 
6 
tt 
12 
u 
tt 
21 
it 
42 
tt 
tt 
15 
tt 
30 
tt 
tt 
1 
a 
2 
tt 
it 
Series D. 
Indifferent . 
The glaucothoe were provided with straight tubes of such 
diameter that they could not twist the body. Glass tubes proved 
the best of the various objects tried. Three experiments, using 04 
larvae, 39 of which reached the moult to the sixth stao*e. No mid- 
period examination. 
% 
35 glaucothoe 89.7 percent remained in stage 5 days. 
4 tl IQ it tt It It 0 It 
