Echinoid' Tests, Ciduroida. 
97 
vvith its downward slope, with the vertical extension of its Perforation, and vvith 
the shape of the platform, is evidence that the radiole borne by it could move in 
a meridional direction but not from side to side; among the numerous radioles that 
are known from Bakony, it is only those of Ancinlocidaris, and more particularly 
the trulliform radioles, that possess an articular surface bearing witness to such 
limitation of movement: in fact, the acetabulum of those radioles, which general 
considerations had already induced me to regard as transversely elongate, presents 
the closest possible correspondence vvith the mamelon of these interambulacrals. As 
will hereinafter be shown, the «testudo» was so constructed that its constituent 
radioles could be depressed but could not be raised or moved from side to side ; 
an articulation such as we here find was therefore a natural consequence. 
The preceding arguments should convince the most sceptical that these inter¬ 
ambulacrals did bear the radioles of Anaulocidaris. It may, however, be objected 
that the experienced and eminent founder of the genus himself described as inter- 
ambulacral plates certain structures which were afterwards proved by others, and 
admitted by him, to be radioles of the shape here distinguished as paletiform ; and 
I may be reminded that the original diagnosis of the genus drew attention to the 
«quer-sechsseitiger oder etwas unregelmässiger Form mit abgeschrägten seitlichen 
und unteren (?) Rändern», and to the «durchbohrte Stachelwarze, die von keinem 
Höfchen umgeben ist» (Zittel, 1879, p. 486). Why, then, may not these supposed 
interambulacrals from Jeruzsälemhegy also turn out to be radioles? 
The resemblance certainly is remarkable, but it is conflned to external form, 
and that only in a general way. The granules or obsolescent miliaries of the plates 
are not found on any of the radioles, which for their part have linear striae; the 
articular surface is a- convex mamelon in the plates, but a concave acetabulum in 
the radioles; the radioles have an annulus and collerette, structures which are quite 
characteristic and not to be confused with the neck, platform, and boss of any 
tubercle, least of all with those structures in the present species; the section of 
the plates (e. g., figs. 167, 180) is quite characteristic and differs from that of any 
paletiform radiole. 
Relations of the Species. — Assuming that these plates are correctly 
placed with the radioles named Anaulocidaris testudo, the only question that arises 
concerning the species as such is the question of its distinctness from Anaulocidaris 
Buchi. This question can only be discussed on the basis of the radioles, and must 
be deferred tili they have been described. These plates, however, throw light for the 
first time on a more important problem, namely — 
The relations of the Genus. — When it was discovered that the supposed 
interambulacrals of Anaulocidaris Buchi were only modified radioles, and when it 
was further asserted (e. g. by Doederlein, 1886, N Jahrb. f. Mineral, I, p. 192) that 
other Cidaridae had radioles similarly modified, then the genus Anaulocidaris was 
hastily dropped, and its genotype resumed its original name — Cidaris Buchi. This 
did not mean that anyone regarded the species as a true Cidaris, for even the 
radioles depart considerably from the normal Cidaris type ; but, in the absence of 
coronal plates, it was impossible to say to which, if any, of the Triassic genera it 
might belong. This then is the first question that has to be answered. 
Among the genera of Echinoidea having but two columns of plates in each 
interambulacrum, the only one with a diagnosis that comes near to admitting the 
Resultate der Wissenschaft]. Erforschung des Balatonsees. I. Bd. 1. T. Pal. Anh 7 
