206 
Triassic Echinoderms of Bakony. 
or obsolescent state in his figure 25. The latter appearance is, in fact, that presented 
by all specimens in which the faint traces of pustulation have not been vvorn avvay. 
The average number of ridges to a millimetre appears to be 3'4, whereas in 
the Cassian radioles examined it was 27. The ribs do not, however, appear so 
much thinner as this might imply, partly because the absolute diameter of the 
radioles is less, partly because the absence of sharp pustules and the reduction in 
width of the grooves between the ridges increase the apparent and the relative width 
of the ridges. 
The base has the same general structure and about the same proportions as 
in the Cassian radioles, but the obliquity is not so marked ; oddly enough, it is not 
shovvn at all in Bhoili’s figures. 
The numerous differences here pointed out are so clear and so constant in the 
material available, that it does not seem right to record Cidaris Hausmanni from 
the Pachycardientuffe without some qualification. These radioles seem to indicate 
a permanent mutation from the Cassian species. 
No examples of this mutation are yet known from Bakony, but they may 
easily have been overlooked owing to their small size. 
Relations of the Species. — With our present knowledge, Cidaris 
Hausmanni appears one of the most distinct of all Triassic Echinoid radioles, 
and yet the small size, the entire absence of dorsoventral compression, and the 
peculiar features of the base render it doubtful whether it is a normal peripheral 
radiole. From whatever region of the test these radioles may have come, we are 
unable to associate with them any known forms that may have come from the 
other regions. In some respects they remind one of the smaller examples of 
C. dorsata , with which indeed Quenstedt confused them. They are also liable to 
confusion with small radioles of C. alata.. These resemblances may depend on 
some actual relationship. 
Cidaris cf. dorsata et Hausmanni. 
(Plate XII, figs. 372—374.) 
Material from Bakony. — The Cassian beds of Cserhät have yielded 
6 very small radioles (a — f ), which, though generally resembling C. dorsata, differ 
so greatly in size from the normal forms that they demand separate treatment. 
A similar radiole (g) comes from the Lower stratified Limestone of Giricses-domb, 
Veszprem. 
Description o f the Specimens. — The following table gives the chief 
measurements in millimetres. 
a 
b 
c 
d 
e 
/ 
£ 
Length. 
. 3-8 
3’8 
4-5 
4'6 
4'6 
3-6 
4-0 
Greatest diameter . . 
• ! 17 
ca. 17 
L3 
17 
2-0 
1 '8 * 
2'1 
h-6 
2-3 
L8 
1‘9 
Diameter at annulus . 
. 0-7 
0-9 
fl 
L0 
LQ 
— 
— 
ln c the shaft is crushed, so that the difference between the diameters is 
exaggerated. ln f the base is broken off. In g most of the base is broken off, so 
that the length probably did not exceed 4'6 mm. 
