Echinoid Radioles, Anaulocidaris. 161 
(BM) In the British Museum. 
-------27°0 from acetabulum 
S18: > » 2°2 thick over all, 1°4 thick in median line 
eer 9:0 » > 3:3 > > > 2°4 » » » 
ew Pees, HAN > BABY es 
\.L...-.--restored acetabulum 
Text-fig, 48. 
Registered E 9351. From St. Cassian, Kuipstem Collection. 
Slightly crushed at proximal end; annulus unknown. 
() . 
is 180 from acetabulum . . . - . ~ J4 thick at point 
i 90. » > 2°3 thick over all, 1°8 thick in median line 
LO}, te > 3°70 » at annulus; width 4°1 
----"-lacetabulum. Height of collerette from annulus 1°4 to 1°6. 
Text-fig. 49. 
Registered E 9352. From St. Cassian, Kutrstein Collection. These two radioles 
are scarcely removed from remiform. ‘There are also in the Kurpstein Collection 
three radioles, more definitely spatuliform, labelled Cidaris Buchi by \.ipsTEin 
(regd. 36524). 
Comparison of the Cassian radioli spatuliformes with those from Bakony, 
shows that, although there are a few quite small specimens, still most of those 
collected are much larger. No radiole from Bakony exceeds 18°3 mm. in length. 
MM, d, RAW, 3b, c, HMW, d, e, 2, BM, d, e, were all well over 20 mm. long, and 
BM, d was probably not the only one that attained 27 mm. Therefore, as with 
the remiformes, the length of the Cassian spatuliformes to that of the Bakony 
specimens is 3:2. The ratio of thickness to length is about the same in the two 
species. The essential difference lies in the median excavation, giving rise to lateral 
ridges, in A. Buchi. The extent of this can be gathered by comparing the thickness 
of the blade over all with the thickness in the median line. Thus in BM, d, at 
9 mm. from the acetabulum the median excavation is 27°2 per cent of the total 
thickness at that level; at 18 mm. the excavation has increased to 363 per cent. 
In this specimen the concavity is particularly evident. In the other specimens the 
maximum excavation is 26°6 per cent (in HMW, g), and the minimum is 12°5 per 
cent (in HMW, ad). It will be observed that the excavation is quite as obvious in 
small radioles as in large ones. The ridges are manifest on the inner face, and the 
excavation of the outer face is very slight or nonexistent. We have already seen 
that many spatuliform radioles of A. festudo have no such concavity, and that, when 
present, it rarely exceeds 12°5 per cent; only in Jeruzsalemhegy g does it amount 
to as much as 20 per cent, and this is quite exceptional. 
Resultate der wissenschaftl. Erforschung des Balatonsees. I. Bd. 1. T. Pal. Anh. ll 
