Echinoid Radioles, 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. 
at 
Text-fig. 19. Cp CD? 
ae is = S 
a b c ad 
Length of blade in median 
iN CR ew oes, a Old, 10:0 9:2 91 
Greatest length of radiole 10°8 12°1 inl) 11°4 
Greatestewidih.  .y - loi 18°2-+- 176 18°5 
Distance of greatest width 
from distal end . . . 42 o'4? 3°3 3:5 
Benpi ote N: sidear = =) 92 12°7 10°0 10°5 
Renpthvot 5 side).  — 9id 11°5? 11°5 3 
Median vertical thickness 
AimequalOl eens ae lira 16 1°5 1°35 
Greatest thickness along 
the sine: 49) : it Nez 16 1:3 & 1°4 
Width at annulus. . . 27 35 33 33 
Thickness at annulus. Le 22 al 
Specimen a is barely distinct from the spatuliformes; the acetabulum is about 
at right angles to the blade. 
In } the distal margin is irregular and probably was broken in life. 
Text-fig. 20. 
Length of blade in median 
ncee pew eee nee a OO 971 86? 68 
Greatest length of radiole . 107 10°4 10°2 ‘ 65 
Greatest width. . . . . 19'2 20°4 20°0 15°] 
Distance of greatest width 
from distal end . » 42 Dal 36 30 
Length of N. side . , 12°5 12°3 11°5 11:0 
Length of S. side . 5 NBR! 13:5 35 10°7 
Median vertical thickness at 
Squat sores. 2) see 3 15 10 
Greatest thickness along the 
Lines 4— Ves 8s = LG 16 eg 1°0 
Width at annulus. . . . 37 37 375 2°65 
Thickness at annulus. . . 2°53 2°6 24 1°75 
