VARIATION IN ECHINOID PLUTEI 693 
//. Left Oral Arm, S Days 
8 
10 
11 
12 
13 
! I 
14, 15 16 
17 
18 
19 
20 
21 
7 
1 
1 
8 
0 
9 
1 
1 
10 
1 
1 
1 
3 
§.11 
1 
1 
Q 12 
1 
1 
1 
1 
1 
2 
7 
13 
1 
1 
2 
1 
5 
§"14 
1 
2 
1 
2 
6 
^ 15 
2 
1 
1 
3 
1 
1 
1 
10 
o 16 
1 
1 
2 
3 
1 
1 
9 
^ 17 
2 
1 
2 
1 
6 
^18 
2 
2 
^ 19 
1 
2 
1 
1 
1 
1 
7 
20 
1 
1 
3 
1 
4 
13 
^ 21 
1 
4 
I 
1 6 
22 
1 
1 
4 
5 
3 
1 
15 
23 
1 
1 
1 
3 
24 
1 
1 
1 
3 
25 
2 
2 
1 
4 
5 
7 
11 
11 
31 13 
4 
19 
14 
4 
3 
1 
