194 Triassic Echinoderms of Bakony. 
To this brief statement may be added the following. The limits of the 
axial complex are not clearly defined, but it seems to merge into an axial lumen, 
probably of variable size. The presence of a definite lumen is proved macro- 
scopically by the crushing of so many of the flatter radioles, and microscopically 
by the occurrence of fragments of other fossils in the central area of the section 
not here figured. The meshes immediately surrounding the lumen have very fine 
walls and are quite irregular, but become more radiate in arrangement further from 
the centre. All these larger meshes are here somewhat arbitrarily assigned to the 
axial complex and give it a diameter of two-fifths that of the radiole. They are 
succeeded by a band of much finer meshes, half their size or less. These latter, 
however, are soon followed by larger meshes, arranged in radiating irregular rows. 
In the other section — across the smaller and more flattened radiole — these 
meshes appear more centrifugally elongate, an appearance possibly due to the 
destruction of some trabeculae. At a short distance from the periphery, equal to 
about 0°65 of the total diameter, the meshes become smaller and the walls between 
them so definitely arranged as to constitute distinct radiate septa with approximately 
equidistant trabeculae. In a more regular meshwork this would have implied con- 
siderable dichotomy of the septa during the inner part of their course, but here 
dichotomy cannot be distinguished except in this outer layer. The number of 
septa cropping out on the surface is about 23 to a millimetre. In the inner layer 
where the meshes are largest, there are about 13 to a millimetre. 
This micro-structure, which, according to Hesse (1900, p. 229) «am weitesten 
vom normalen Cidaris-Typus entfernt sich», is only an exaggeration of the micro- 
structure seen in C. Wissmanni (Pl. XV, fig. 445), where, on the same authority 
(p. 227) «das mikroskopische Bild des normalen Cidaris-Typus bis ins Kleinste und 
in grésster Scharfe ausgepraégt». The difference lies in the greater coarseness of 
mesh throughout, and more particularly in the greater coarseness and irregularity 
of the layer next to the axial complex. The micro-structure of C. similis is far 
more distinctive, and it is curious that the species usually confused with C. Waechteri 
(= Brauni) should be not C. Wissmanni, which really presents a strong likeness, 
but the more remote C. similis. 
In view of the comparison made by Mobnster of C. Waechteri to C. alata, 
it may be noted that in micro-structure the former is nearer C. dorsata. 
Material from Bakony. — The scarcity of the species is remarkable. 
The Cassian beds of Cserhat (Leitnerhof) have yielded only three specimens, and 
three insignificant fragments come from the Cassian bed e 4 of Section VI, Veszprem. 
These specimens all indicate smaller radioles than those common at St. Cassian. 
The only perfect one among them is the smallest (Pl. XII, figs. 347, 348). Length, 
7°2 mm. Greatest diameter: transverse, 1°55 mm.;_ sagittal, 1°15 mm. Diameter at 
annulus, 0°8 mm. _ It has serrate margins, and on each face three rows of pustules, 
making 8 rows in all. The distinction between the faces is slight, but the supposed 
adapical face may be identified by the proximal curvature in that direction of the lateral 
lines of pustules, as in C. alata. The annulus is not very distinct, but appears to 
slant towards the proximal end and adoral face. 
Of the larger fragments from Cserhat, one comes from the proximal region, 
the other from the distal. That from the proximal region (Pl. 350, figs. 351) is 
slightly the thinner and is more compressed, its diameters being 3°8 and 3°0 mm. 
