Echinoid Radioles, Cidaris dorsata. 179 
spaced and sometimes dichotomous, radiating from the axis, and separated by irre- 
gularly spaced trabeculae, radiate septa of outer layer finer and more regular; radiole- 
shaft normally pyriform or subclaviform, without clearly differentiated handle, but 
covered with pustulate ornament, which may be in linear series but very rarely 
forms distinct ridges, or may be spinulose. All radioles, except a few circum-apical, 
dorso-ventrally compressed, but the compression is as a rule slight and not more 
marked in the peripheral radioles. Pustulation as a rule slightly more marked on 
the adapical face. Collerette short, with fine longitudinal striae. 
Lectotype: the original of MOnstrr (1841) pl. iv, f. i. a; from the St. Cas- 
sian beds of St. Cassian district. 
As in the case of Cidaris alata, the Raiblian specimens of this species repre- 
sent a distinct mutation, of which the characters are chiefly manifest in the presumed 
supra-ambital radioles. The mutation may be called marginata, and the St. Cassian 
forms distinguished as typica. 
«Cidaris» dorsata typica. 
(Plate XI, figs. 310, 311 and Plate XIV, fig. 438.) 
Diagnosis. — C. dorsata in which the pustules on the radioles are as a 
rule low and not elongate; in which the distal end of the supra-ambital and adapical 
radioles is conoid or rounded, and not limited by a rim. 
Holotype. — The same as the lectotype of the species. 
Material from Bakony. — The norm of this species appears to be 
represented by various fragmentary and ill-preserved radioles from the Cassian beds 
of the following localities: Cserhat (Leitnerhof), two or three fragments; Veszprém, 
Giricses Domb, lower stratified limestone, a subclaviform shaft; Veszprém, Taka- 
rékpénztar, a large shaft; Section V1 Veszprém, a weathered proximal fragment ; 
the same, bed e 3, fragment of a globular shaft. 
Remarks on the specimens. — These present the various shapes and 
modes of pustulation noted in the Cassian specimens (Monster, 1841, pp. 46, 47). 
It may be surmised that the more baculiform and pyriform radioles are peripheral, 
that the subclaviform and claviform are supra-ambital, and that the globiform or 
rapidly expanding radioles are adapical. 
The dorso-ventral flattening characteristic of the species is best seen in the 
subclaviform shaft from Giricses Domb (fig. 311). This is 14°7 mm. long with 
greatest diameters 7°2 mm. and 6°4 mm., and may be regarded as of average size. 
The shaft from Takarékpénztar (fig. 310) is much split, but when complete 
must have exceeded a length of 40 mm.; its greatest diameters are 13°5 and 12 mm. 
This does not approach the swollen rounded shape of C. gigantea Cornatia, nor are 
its pustules arranged in similar longitudinal series. 
The fragments from Cserhat are rather doubtful. One of them possibly had 
an axial cavity, and if so cannot belong to this species. 
Considering the abundance of Cidaris dorsata at St. Cassian, where it is said 
to be the commonest Echinoid fossil, its meagre representation in the Cassian rocks 
of Bakony is remarkable. 
Some very small radioles, possibly belonging to this species, are dealt with 
on a later page, under the heading «Cidaris» cf. dorsata et Hausmanni. 
12* 
