34 
Triassic Echinoderms of Bakony. 
concavity, which, hovvever, may be due to weathering. Only one specimen, a fragment 
from Jeruzsälemhegy (fig. 41), approaches the shape characteristic of the typical 
I. tyrolensis, in that along the suture-lines in the reentrant angles there are peculiar 
swellings, which make the side-faces concave radially, whereas they are slightly 
convex interradially. A sub-pentagonal specimen from the same locality also shows 
slight ridges along the sutures. 
Nodals not more swollen than internodals. 
Surface smooth. 
Suture-line crenelate all round, except at the syzygies. Crenelation more pro- 
nounced at the interradial angles. 
Joint-faces. — Normal: (figs. 39, 40) Lumen minute, subcircular or subpentagonal 
with interradial angles. Central area raised, continuous with radial ridge-groups. 
Petal-floors depressed, narrow, and either lanceolate or elongate petaloid, the greatest 
width being in their distal half. Radial ridge-groups of 2 to 5 pairs, of which the 
acentral crenellae, which are the larger, meet in a gable, while the adcentral ones 
lie straight across the radius. Peripheral crenellae in a petal vary in number, from 8 
in a columnar of 2'2 mm. diameter, to 14 in one of 4 mm. diameter; the increase 
in number is correlated partly with the increase in diameter, partly with the greater 
depth of the radial excavation, since the nearer the section is to a pentagon, the 
more crenellae merge in the perradial series. The adradial peripheral crenellae 
requently meet at their outer ends, forming a gable. The peripheral crenellae diverge 
fan-wise from the interradius, sometimes straight, sometimes curving towards the 
interradius at their outer ends like the seven-branched golden candlestick. The 
crenellae widen towards their outer ends, but are never confluent. The following 
measurements in millimetres are taken from a normal columnal: diameter, 3*7; 
ength of IR, 1 '85; length of r, 1*4; length of shortest crenella, 0*3; length of 
longest crenella, 0*6; width of crenella, 0* 1. 
Syzygial: Epizygal (figs. 42, 46), resembles normal joint-face modified as 
follows: radial regions raised as rounded ridges above the indented cirrus-facets 
(vide infra), broader towards the periphery, where the cirri emerge, and scarcely 
marked at all by crenellae; thus the rosette is more lobate, and the petals some¬ 
times narrower, even adcentrally; peripheral crenellae also shorter, less distinct, and 
not so clearly separated from the petal-floors, so that each petal assumes a more 
hollow shape. Hypozygal (fig. 43), resembles normal joint-face modified as follows: 
lumen appears relatively large, pentagonal with radial angles, and probably comprises 
a depressed central area; petal-floors raised and swollen to fit into the hollows of 
the epizygal; radial spaces depressed to receive the radial ridges of the epizygal 
and the proximal cirrals, narrowing adcentrally into a slight radial groove, which 
runs right up to the lumen (or depressed area) and separates the adradial crenellae; 
crenellae faint, and continuous right round the petal. 
Cirrus-facets (figs. 41, 42, 44—48). — Five on each nodal, in its lower part, 
indented in the radial re-entrant angles, to form deep, almost V-shaped excavations, 
abutting in either whole or part on the hypozygal, and indenting that also, though 
to a less extent. Thus, even in the least lobate columns, the epizygal is strongly 
lobate; but this can scarcely be detected from the side, since, owing to the depth 
of the indentation, the proximal cirrals are usually preserved, and all that is visible 
from outside is the joint-face of cirral 1 or 2. Removing these cirrals, one sees at 
