Bd. VI: 4) 
THE ECHINOIDEA. 
37 
ever, most of these are calculated in percent I give here some direct measurements, 
finding that it may not infrequently be preferable to have the direct instead of the 
percent numbers; further these measurements will be of importance for judging of 
the value of the varieties of this species established by DÖDERLEIN. 
Dia- 
meter. 
Height. 
Peri- 
stome. 
Apical 
system. 
Anal 
area. 
Width of 
Number of plates. 
Longest 
spines. 
Ocular 
plates 
conti- 
guous 
with the 
anal area. 
ambu- 
lacra. 
inter- 
ambu- 
lacra. 
Ambu- 
lacra. 
Inter- 
ambu- 
lacra. 
mm. 
mm. 
mm. 
mm. 
mm. 
mm. 
mm. 
mm. 
4 ° 
25 
IO 
13 
6.5 
9-5 
16 
25 
18—19 
7 
II, V. 
38 
24 
1 1 
12 
6 
9 
* 4 ' 5 . 
25 — 26 
19 — 20 
10 
I, V. 
Stat. 
44 
37 
27.5 
IO 
12 
6 
9 
H 
24-25 
l8 — 19 
8 
I, II. 
36 
22 
10 
12 
7 
9 
13 
24-25 
17—18 
I, II. 
36 
20.5 
II 5 
i°. 5 
6 
9 
* 3-5 
23—24 
18—19 
— 
I. 
305 
16.5 
9-5 
IO 
6 
7-5 
h. 5 
21 
15 — 16 
— 
I. 
27-5 
16 
8.2 
8 
4 
7 
10 
20 
15—16 
— 
I. 
26 
14.5 
S.? 
8 
4.2 
7 
9-5 
19 — 20 
H - >5 
9-5 
I. 
26 
13-5 
8 
7.8 
5 
7 
9-5 
19—20 
15 
1 1 
I. 
Stat. 
2 
25 
c 
8 
7 
4 
7 
9 
20—21 
l6 
8 
I. 
24.5 
14-5 
9 
7.2 
3-5 
6.2 
9 
21 
15—16 
— 
I. 
24 
! 4 s 
8.2 
7 
3-5 
6.5 
8.8 
20 
16 
— 
I. 
24 
H 
8 
7-5 
4-5 
6 
9 
20—21 
16 
9-5 
I. 
22 
•3 
7 
7-5 
4 
6 
8 
19 
H 
9 
I. 
16 
9-5 
6.5 
5 
2.5 
4-5 
5.2 
17 
12-13 
• — 
I. 
Isthm. 
Bay 
26 
16 
9 
6. s 
3-5 
6.2 
9.6 
24-25 
17—18 
— 
I. 
24.5 
*5 
7.8 
6.8 
3 
6 
9 
23 
15—16 
— 
I. 
23 
13 
7-5 
7-5 
3-5 
6 
8 
21 
16—17 
— 
I. 
Ultima 
Esperanza 
23 
* 3-5 
7-5 
8 
3*5 
5.8 
8 
20 
14-15 
5-5 
I. 
22 
14-5 
7 
7.2 
3-8 
6 
7-5 
20—21 
16—17 
10 
I. 
21.5 
13 
7-5 
6.5 
2-5 
5-5 
8.2 
20 
15 
6.5 
0. 
Stat. 
3 ! 
21.5 
II. 5 
8.5 
5.8 
3 
5.2 
7.6 
1 9 
J 4 — 1 5 
— 
i. 
1 
17 
IO 
6.8 
5 
2.6 
4-5 
6 
18—19 
H 
— 
i. 
Concerning the tuberculation it may be remarked that the secondary tubercles 
are, upon the whole, very varying in size and number; in some specimens they 
form very conspicuous vertical series, in others they are all of almost uniform small 
size, scarcely forming distinct vertical series. The areoles of the primary inter- 
ambulacral tubercles are small and, generally, not in contact, except a few of those 
nearest the peristome; even at the ambitus they are separated by a series of miliary 
tubercles. In the ambulacra the areoles are generally in contact, probably always 
at the ambitus, at least in larger specimens, sometimes along the whole series from 
the peristome to the apical system. 
