136 
Triassic Echinoclerms of Bakony. 
Most English writers have used condyle, which properly indicates a convexly rounded articular 
surface, and is therefore quite inapplicable. The French and German equivalents are facette 
articulaire and Gelenkfläche. 
Variation and Specific characters in the Radioles. — Some 
of the radioles from these Triassic beds are so distinct in form or Ornament that there 
is no great barm in assigning them to distinct species. Otbers, however, seetn to 
bave so wide a ränge of Variation that there has been constant disagreement as to 
the limits of the species. Koechlin-Schlumberger (1855) has probably gone furthest 
in reducing the number of species erected by previous authors, and if it were 
possible to follow his lead without question, the work of determination would be 
greatly simplified. But there is much common sense in Broili’s position (1904) 
that, since the various forms have been described, and can readily be recognised 
in most cases, therefore it is as well to denote them by the names generally adopted. 
A more rational basis, however, is desirable, and as a help towards its attainment 
it will be well to consider the kinds of Variation that are to be expected in these 
radioles. 
Limiting the discussion to primary radioles, one notices in an individual echinoid 
that there is not merely slight Variation between radioles of the same rank, but a 
definite gradation of form according to the position of the radiole on the test. In some 
of the Cidaridae, notably Goniocidaris clypeata Doed., this is conspicuous, and 
there can be no doubt of its occurence in many of these Triassic echinoids. The 
abundant material of Anaulocidaris testudo has permitted the reconstruction of the 
entire series of radioles, thus confirming opinions previously expressed concerning 
the rare specimens of A. Buchi. In other Triassic species the Variation appears to 
have been of the same character, which is in the main as follows. The radioles 
of the adoral surface are relatively small, and in shape approach a simple and 
probably primitive type. They may be cylindrical, slightly club-shaped, or slightly 
spatulate. Doederlein has also renrarked on their deficiency of Ornament. Probably 
it would nearly always be impossible to distinguish between allied species by means 
of their adoral radioles. The radioles on the periphery are relatively elongate and 
distinctly bilateral, having the adoral surface difi'erent from the adapical and usually 
with less pronounced Ornament; the radiole is frequently bent downwards, so that 
the acetabulum, besides being widened transversely, is not at right angles to the 
axis of the shaft. The downward bending permits one to describe the adoral surface 
as «inner«, and the adapical surface as «outer». These peripheral or ambital radioles 
appear to be the ones that show most clearly the characters of the species. In the 
circumapical, or more briefly «apical», radioles those characters are slightly obscured 
by a further modification: the radiole resumes a position at right angles to the 
test, and becomes relatively shorter; frequently it expands distally, sometimes so 
much as to assume a mushroom shape, and may develop pronounced pustules or 
spinules. Whereas the ambital radioles are probably used in locomotion or for 
anchoring the animal, these exp>anded apical radioles probably serve as a protection 
to the whole animal and especially to the organs of the apical System. Remarkable 
examples of their modification are known from recent seas, such, for instance, as 
those figured by Doederlein (Japanischen Seeigel, pls. VI, VII), but that distinguished 
authority now proves incorrect in his Statement (op. cit. p. 34) that these broadened 
ends first occur in the Chalk, for scarcely less remarkable are some of the Triassic 
