Echinold Radioles, Cidaris Wissmanni. 197 
The micro-structure consists of an axial complex, which, in the cross sec- 
tion studied (Pl. XV, fig. 445), occupies about one-fourth of the total diameter, and 
is transversely elongate. This is surrounded by a layer of relatively large, irregular 
meshes, which gradually become smaller and arranged in rows radiating from the 
centre. The radiate septa are fine, distinct, occasionally dichotomising, so that on 
the periphery their number is just double that.at their commencement, and they are 
a little closer together. Owing to the dichotomy they wave slightly. The trabeculae 
also are fine and distinct, enclosing fairly regular, square or elongate meshes. 
Near the periphery the septa are about 37 to the millimetre, and nearer the centre 
about 32. 
The difference between this micro-structure and that of C. similis is remarkable 
considering the resemblance of outward form. 
Except for its far greater regularity and the greater fineness of mesh, the 
micro-structure rather resembles that of C. Waechteri, a species with which Cidaris 
Wissmanni is also liable to be confused (see p. 194). The differences of outer 
form are chiefly the thin baculiform shape and the distinct thornlike pustules of 
C. Wissmanni, as opposed to the widening and compressed or claviform shape and 
the smaller often confluent pustules of C. Waechteri. There are, however, many 
specimens that cannot be determined with certainty, at least in the absence of 
microscopic examination. 
Material from Bakony. — The radioles that can with least doubt be 
referred to this species are all of Cassian age and come from the following local- 
ities: Cserhat (Leitnerhof), 40 specimens; Section VI, Veszprém, bed e, 1 specimen, 
bed e 4, a doubtful fragment; Veszprém, Giricses-domb, Lower stratified Lime- 
stone, 4 specimens. From the same localities come other radioles that may represent 
one or two varieties of this species, while a third form is found in the Raiblian of 
Jeruzsalemhegy ; to these we shall return. 
Even the more normal radioles comprise several different forms. The form 
most like the holotype is represented by the specimen from Section VI, and by two 
from Giricses-domb. Of these the first is the proximal end of a flattened radiole, 
with diameters 2°56 and 1°1 mm., with flattened, almost smooth adoral face, with 
prominent thorns along each side, and with two or three irregular rows of some- 
what thorn-like pustules on the adapical face. Of the two from Giricses-domb, one 
is a fragment of the shaft, 935 mm. long, not flattened, with diameter 2°1 mm., 
and with slightly thorn-like pustules so irregularly set that longitudinal rows can 
scarcely be said to exist, but about 8 pustules surround the shaft at any level. The 
other specimen appears to be the distal end of a shaft, 6 mm. long, very slightly 
flattened, with diameters at the thicker end 1°6 and 1°45 mm., thence gently tapering 
to the extremity; its pustules have the general character of those in the preceding 
specimen. These two specimens show traces of an axial lumen or, it may have 
been, a very loose axial complex. 
Several of the Cserhat specimens are also fairly normal, though it is some- 
times difficult, in the absence of micro-sections, to distinguish them from C. Waech- 
teri. Some twelve may be separated as thin, with sparse thorn-like pustules (PI. XII, 
figs. 353, 354.); their diameters range from 1‘1 mm. to 2°7 mm.; some are slightly 
flattened ; their pustules often tend to arrange themselwes in rows, sometimes long- 
itudinal but frequently oblique, and those in a row may be connected by a slight 
