186 
Triassic Echinoderms of Bakony. 
but on the ribs they are coarser. These striae, which represent the edges of the 
radiate septa of the stereom, are broken up into granules, which vary in intensity. 
Laube describes them as punctate («dunktirte» sic); but the punctate appearance 
arises only when the Ornament is worn, so that one sees the trabeculae uniting the 
radiate septa, and the «punctae» between them. 
The Originals of Laube’s figs. 5 c, d, e do not seem to be of this species. 
Their outline is different, since they suddenly swell out; also the numerous pus- 
tules and spinelets following the course of the ribs are much stronger than the 
almost microscopic granules of the normal C. decorata. 
ln a few well-preserved radioles of C. decorata, however, the granulation 
assumes a shagreen character coarser than the striation. It then forms a distinct 
cortical layer, covering the radiate septa. Both the shagreen cortex and the septa 
exposed vvhere it is eroded are clearly seen in two fragments from St. Cassian 
(Brit. Mus., E 1024). 
The micro-structure is shown in a section of a similar fragment (Brit. Mus., 
E 4607 ; PL XV, fig. 442). The cortex is here seen to be formed by the suddenly 
widened and closely abutting outer ends of the radiate septa. It does not form a 
layer so distinct in structure as in some later Cidaridae, and its thickness is there- 
fore indefinite, but may be taken as from 0T to 0'2 mm. The layer of radiate 
septa is about 0'9 mm. thick. The septa are wedge-shaped, increasing somewhat 
more rapidly in thickness towards the periphery. They are slightly grouped in fan- 
shaped fascicles under the ribs, and may dichotomise occasionally near their origin. 
They Start from a thin layer of fine irregulär meshes. Within this is the axial 
complex of much larger, very irregulär meshes, which seem to become rather smaller 
towards the centre. Probably there was irregulär resorption about the axis of the 
radiole, so that in some specimens there seems to have been a large axial canal, 
now rendered visible by the coloured matrix, while other specimens show no trace 
of this. In the section described it is hard to see whether there is any axial stereom 
or not. From the centre outwards, the thickness of the axial complex is about 1*47 mm. 
Therefore in a transverse section of a radiole of diameter 100, the relative 
thicknesses are cortex 3, septal layer 18, total diameter of axial complex 58. 
Specimens from the Pachycardientuffe of the Seiser Alp do not markedly differ 
from the St. Cassian radioles. Those available (Brit. Mus, E 4614 and E 4696) 
incline to be relatively thinner, and with the dorso-ventral differentiation more marked 
owing to the absence of ribs on one face (? the adoral); several, rather small 
specimens, are figured by Broili. 
Material from Bakony. — The Cassian beds of Cserhät (Leitnerhof) 
have yielded a few, generally weathered fragments, which may belong to this species, 
though it is hard to distinguish them from fragments that probably belong to Cidaris 
fasciculata. Unfortunatelv microsections showed no structure. The distal end of 
a radiole, probably of C. decorata, has been found in bed e4 at Section VI, Veszprem. 
From the Raiblian beds of Jeruzsälemhegy comes the distal end of a radiole, 
7 X 1’5 mm., with six ribs (fig. 342). In this fragment longitudinal striae are seen 
in the intervals between the ribs, and the characteristic micro-structure can be made 
out on the broken proximal end. The striae are finer than in normal Cassian 
specimens, being about 35 to the millimetre. This greater fineness of striation 
has also been noticed in the specimens from the Pachycardientuffe. 
