Echinoid Radiales , Anaulocidaris. 
151 
most closely correlated with the position of the radiole on the test. With the 
specimens so arranged, it is seen that the blade first increases in width and in 
angularity until an acme of relative width is reached; then, without decrease in 
angularity, and in fact with increase in the straightness of the sides, it decreases 
in relative width, and this decrease is more rapid at the S. margin and less at the 
N. margin, with the result that the SW. and SE. sides increase in relative length. 
At the same time there is a decrease in absolute size. 
JE 
Text-fig. 19. ( 
C 7 
/G ' ^ 
v V • 
Length of blade in median 
a 
b 
c 
d 
line .. 
87 
io-o 
9'2 
97 
Greatest length of radiole 
10'8 
127 
1L3 
1L4 
Greatest width .... 
Distance of greatest width 
15-5 
18'2+ 
176 
18-5 
from distal end . 
4'2 
5'4? 
3'3 
3'5 
Length of N. side . 
9'2 
127 
io-o 
10'5 
Length of S. side . 
Median vertical thickness 
9'5 
11'5? 
11-5 
11-3 
at equätor. 
Greatest thickness along 
L3 
1'6 
L5 
L35 
the line *— y .... 
LI 
17 
L6 
1‘3 & 1'4 
Width at annulus . . . 
2'7 
3*5 
3-3 
3'3 
Thickness at annulus. 
17 
2'2 
2-2 
27 
Specimen a is barely distinct from the spatuliformes; the acetabulum is about 
at right angles to the blade. 
In b the distal margin is irregulär and probably was broken in life. 
e 
Length of blade in median 
line ........ 9'5 . 
Greatest length of radiole . 10'7 
Greatest width . . . . . 19"2 
Distance of greatest width 
from distal end .... 4'2 
Length of N. side . . . . 12'5 
Length of S. side .... 13*8 
Median vertical thickness at 
equator....... 1 '5 
Greatest thickness along the 
line *— y ...... 1'6 
Width at annulus . ... 37 
Thickness at annulus. . . 2'3 
/ 
s 
h 
97 
8'6? 
6'8 
10'4 
10'2 
7'65 
20'4 
20'0 
157 
37 
3'6 
3'0 
12'3 
11 '5 
1L0 
13'5 
135 
107 
1 '3 
1'5 
L0 
1'6 
17 
L0 
37 
3'5 
2'65 
2'6 
27 
175 
