146 Triassic Echinoderms of Bakony. 
Text-fig. 16. 
p q r KY 
Length? 5: See a5 tere) coy, eet M5 10°4 10°2 
Greatest. width: 9° 745500e seu ee lator 15:0? 155. 16°2 
Distance of greatest width from distal 
end( se ee ? ? 4°2 47 
Thickness at same level. . . 2) AGS 16 12&1°45 19 &23 
Greatesty thickness: 2 are ees Bie me 26 
Distance of same from distal end. . ? ? 82 84 
Least width at collerette. . . . . 28 2°8 2°8 27 
Thickness at same place. . . . . 20 15 ry = 
Width atannulus .. . pee ell 370 30 — 
hickness at‘annulus;. "ee ene) eee 18 ew —_— 
Distance of annulus {\on outer face. 1°3 _ 1°0 — 
from acetabulum fon inner face . 1°6 15 1°3 == 
Distance from annulus | on outer face. ? —- ? = 
to rim of collerette \/on inner face. ? 05 ? _ 
In this series we trace a gradual reduction of length resulting in a relative 
increase of width. The absolute increase in width is not so marked. In correlation 
with this, the line of greatest width moves absolutely nearer to the base, but at 
the same time is nearer the distal margin. The handle of the radiole no longer 
makes a gentle curve with the blade, but is bent at an angle to it in the region 
of greatest thickness, which angle gradually increases, thus diminishing the length 
of the radiole. The outline of the blade, from being somewhat racquet-shaped, 
gradually tends to a roughly hexagonal shape, wider than high, with the distal 
margin and the two distal sides fairly straight, but with the proximal margin, taken 
as coinciding with the line of greatest thickness, forming a curve, convex towards 
the base of the radiole, and merging into the proximal side of the hexagon. 
The blade thins gradually to its free periphery, especially in the distal region; 
the proximal margins, being nearer the line of greatest thickness, are not so sharp 
as the distal ones. The outer or adapical surface of the blade has a slight convex 
curve. The inner surface of the blade is in some specimens slightly concave, as 
may be seen by examining the measurements of thickness in the line of greatest 
width. The concavity is only about 0°1 or 0°2 mm..(=1/, the whole thickness), 
very rarely more and usually less. In the wider and more hexagonal forms, this 
concavity of the inner and convexity of the outer surface passes into a new feature, 
namely a slight bevelling of the proximal sides of the hexagon on the outer surface, 
combined occasionally with a very slight bending of those edges on the inner 
surface. As may be learned more easily from the trulliform radioles, this bevelling 
of the edges indicates that the blades of the adjacent adapical radioles overlap 
these edges by their distal margins. 
The collerette is often indistinctly separated from the proximal part of the 
shaft (or handle). In many specimens the striation is not clear on the blade, and, 
