218 Triassic Echinoderms of Bakony. 
The micro-structure is well shown in two sections, and differs slightly in 
each. In both there appears to be an axial lumen, occupying about 0°13 of the 
total diameter. This lumen is ill-defined, and is doubtless produced by the breaking 
down or resorption of an axial complex. It is immediately surrounded by a layer 
of very irregular meshes, which soon merge into a broad layer of more regular structure. 
In one section (PI. XVI, fig. 450.) this layer consists of meshes arranged along lines 
radiating from the centre, but the meshes are not so regular that their walls can 
be said to constitute radiating septa. Gradually, however, they become more regular, 
and, at about three-quarters of the distance from the centre to the circumference, 
merge into the outer layer of regular radiate septa. In the other section (PI. XVI, 
fig. 51.) the meshes rapidly assume a regular arrangement, separated by radiate 
septa, but, at about two-fifths of the distance from centre to circumference, they 
become irregular and the course of the septa can no longer be distinguished. Then 
at about four-fifths of the distance the septa re-appear and rapidly dichotomise, forming 
an outer layer of finer mesh. On the periphery the septa are about 40 to the 
millimetre, but seem to become rather wider apart on the pustules. 
Relations of the Species. — Just as the outer form is in several 
respects intermediate between Cidaris Waechteri.and C. Wissmanni, so the micro- 
structure resembles that of C. Waechteri in general plan, but has the greater 
fineness characteristic of C. Wissmanni Some of the specimens remind one of 
the much smaller C. Wissmanuni var. rudis, and the ornament of others resembles 
that of the smoother ovoid radioles provisionally associated with that variety. The 
form might perhaps be regarded as a Raiblian mutation of C. Wdussmanni, but, 
even so, it seems sufficiently distinct to claim specific rank. At any rate Radiolus 
raiblianus cannot be confused with any other species from Bakony. 
Radiolus penna* n. sp. 
(Plate XIII, figs. 404—412.) 
Diagnosis. — Peripheral radioles having a solid feather-shaped shaft, 
usually smooth, with stout mid-rib and vanes of equal width distinguishable only in 
adapical view; aeetabular border smooth; annulus crenelate. The length of radiole 
(circa 15 mm.) being taken as 100, length of base is circa 9, diameter of annulus 
13—15, and greatest width of shaft 33. 
Material. — Five fragmentary peripheral radioles from the Raiblian of 
Jeruzsalemhegy a, b, c, d, e, of which a@ is selected as holotype. Two radioles 
(f & g) from the Cassian bed e 4 at Section VI, Veszprem, may be related 
Description. — Specimens a (figs 404—406) and b (figs. 407—409) retain 
the base and what appears to be about half the shaft. Total length of radiole 
estimated at about 15 mm. 
Base smooth, from acetabulum to top of annulus 1°4 mm. Annulus faintly 
crenelate; width, sagittally 2 mm., transversely 2°3 mm. Collerette about 0°6 mm. 
high, separated from the shaft by a fine incised line, and slight sharp step, preserved 
on the supposed adoral side of a; diameter, sagittally 1°8 mm., transversely 1°9 mm. 
From here the shaft continues at nearly the same diameter for about 1°8 mm., 
when it gives off on each side a sharply marked vane. On the supposed adoral 
* Penna, a quill-feather. 
