154 
Triassic Echinoderms of Bakony. 
Text-fig. 25. 
j 
Length of blade in median line 8'5 
Greatest width of blade . . 10'6 
Length of N. side .... 7'0 
Length of S. side . 37 
Thickness at the centre of 
the blade.0'7 
Greatest thickness along the 
line x—y . l’O 
Width at annulus . . . . 2'1 
Thickness at annulus . . . L6 
6'4 
97 
5‘8 
3 3 
0 - 75 
LO 
1 '8 
L6 
5‘9 
81 
6‘0 
3’3 
l'O 
0'8 
o 
87 
9-2 
6 "5 
1 '25 
LI 
175 
L9 
L85 
Text-fig. 26. 
Q 
Q 
Q> 
Q 
p 
9 
r 
U 
V 
Length of blade in median line 6'6 
6-0 
6-2 
6’2 
6'8 
Greatest width of blade . 
. 7*6 
6-3 
67 
6-4 
7-3 
Length of N. side . . . 
. 4'3 
3-5 
4'6 
3'6 
5'0 
Length of S. side . . . 
. 0 
0 
0 
0 
0 
Thickness at the centre 
of 
the blade. 
. 17 
LO 
LO 
0-8 
09 
In these five the annulus is not preserved well enough for measurement. With 
the elimination of the S. side the measurement *—y can no longer be given. 
Of the 23 specimens, 15 have 6 sides, 7 have 5 sides, and one is just on 
the turn. The six-sided blades broadly resemble the trulliformes, but show an 
approaeh to the five-sided outline. They present the following combination of char- 
acters : the S. side is shorter than the N. side; the handle is removed from the margin 
of the blade, and is set either at right angles to the blade or so nearly at right 
angles that it cannot be seen from above when the radiole is laid on a horizontal 
plane with the outer face uppermost; thus the handle does not enter into the 
measurement of the greatest length of the radiole, as it does in the trulliformes, 
and the distance from the acetabulum to the distal margin is actually less than the 
length of the blade. 
The change from the six-sided to the five-sided outline is due to the shortening 
and final disappearance of the S. side. The handle, which gradually moves nearer 
the centre, thus comes to lie about the middle of the line joining the SW. and SE. 
angles. It is not easy to Orient all the five-sided blades, but in most cases the N., 
NE., and NW. sides are still distinguished by the bevel on the inner face, while 
there are still traces of the bevel on the outer surface of the SW. and SE. sides. 
The handle and base afford little help in orienting, since the handle becomes more 
concentrated and therefore more cylindrical, while the base, perhaps owing to the 
greater relative length and slenderness of the handle, is frequently broken off. 
