eh eee eee 
Echinoid Radioles, Cidaris parastadifera et decoratissima. 215 
might be compared. The ribs of that species are finer and the pustules smaller, but it 
is rather the similarity of the micro-structure to which I would direct attention. There is 
in C. Hausmanni (Pl. XVI, figs. 448, 449) the same curious fanning and crossing 
of the septa, a structure to be seen in no other Triassic species. The oblique 
base of C. parastadifera is another point of resemblance, though it is not so 
marked as in C. Hausmanunt. 
It appears then that the Cassian species most nearly related to C. parastadifera 
are C. similis and C. Hausmanni ‘This further suggests that C. Hausmanni may 
represent the circumapical radioles of C. similis, just as the subclaviform radioles 
here assigned to C. parastadifera probably represent the circumapical forms of the 
Raiblian species. Should this suggestion be confirmed, it would certainly help to 
elucidate the curious micro-structure. 
«Cidaris» decoratissima. 
(Plate XIII, figs. 393398.) 
1865. Cidaris coronata Go.pFuss, K. E. SCHAFHAUTL: N. Jahrb. f. Mineral., 1865, p. 790, pl. v, f. 1. 
1889. Cidaris decoratissima S. v. WOHRMANN: Jahrb. Geol. Reichsanst. Wien, XXXIX, p. 196, pl. v, f. 20 
Diagnosis. — A Cidaroid in which the primary spines have a probable 
micro-structure of regular radiate septa and regular trabeculae in the collerette, but 
irregular wavy septa and curved trabeculae in the shaft, probably enclosing a lumen 
or loose axial complex; shape baculiform or fusiform; shaft ornamented with strong 
longitudinal ribs, more or less broken into pustules in the proximal region; collerette 
Striate, long (or short); annulus rounded, striate; acetabular margin prominent 
coarsely crenelate. 
Lectotype, the radiole figured by ScuarnAutn (1865, pl. v, f. 1), from the 
Raiblian Ostreenkalk of the Zugspitze, Wettersteingebirge, also figured by Wo6urMann 
(1889, pl. v, f. 20), and now in the Palaeontological Museum, Munich. 
The localities given by WoOurmann (1889, p. 196) are «Ostreenkalk vom Wetter- 
steinzug, Kienleiten und Judenbach». 
Description of the Lectotype. — A complete primary radiole 
(Pl. XIII, fig. 398.), sub-baculiform, swollen in lower third of shaft. Length, 19°3 mm. 
Greatest diameter, which is about 10°56 mm. from acetabulum: dorsoventral, 3°75 
mm. ; transverse, 3°9 mm., i. e. O'2 of length. Thence the shaft tapers to 1°5 mm. 
at distal end, finishing abruptly in an almost flat top; and to 3 mm. at proximal 
end, about 7°4 from acetabulum. 
Shaft ornamented with longitudinal ribs, of which 10 reach its distal end, 
where, as seen from above, they resemble equidistant septa meeting in a granular 
columella. These ribs run almost straight to the proximal end of the shaft, and 
between them at that end are ten other ribs of equal, or even of slightly greater, 
size, which die out at about 1°5 mm. from the distal end. On one face of the 
shaft all these ribs are strongly and equally developed, with grooves of about the 
same width between them, and on this face, at the thickest part of the shaft, the 
width of a rib and a groove is almost exactly 05 mm. On the other face, the 
ribs are finer, and at about the thickest part of the shaft there are intercalated 
between them incipient ribs, of which one is 4°7 long, while the others are little 
more than scattered granules. Extreme height of ribs from bottom of grooves 
