234 Triassic Echinoderms of Rakony. 
and it may be that the occasional appearance of a lumen is due merely to the 
looser structure of the stereom. Having regard to this statement, and also to the 
fairly frequent occurrence in C. lineola of a collerette and of bicarinate and muricate 
forms, none of which have yet been described in undoubted C. grandaeva, it seems 
better to retain this Keuperian species distinct from the Conchylian, especially as 
its test is still uncertain. 
Wonurmann (1889, p. 195) compared with Cidaris grandaeva both the radiole 
and the interambulacrals referred by him to C. Schwageri. We have already seen 
that the striation of that radiole is far coarser than the striation in C. grandaeva, 
and in this Wourmann’s holotype differs from the equal sized and somewhat similar 
Radiolus lineola minor. The interambulacral plates ascribed to C. grandaeva are 
said to have crenelate main tubercles, and probably belong to Miocidaris. 
WourMann’s remark, however, suggests that R. lineola minor may have 
belonged to Mesodiadema latum. ‘The two forms are found at precisely the same 
localities. This, however, is not proof, for some radioles have to be found for 
Mesodiadema margaritatum (p. 117). Possibly the smooth radioles belonged to 
one species of Mesodiadema, and the muricate or carinate radioles to the other. 
Some also may have belonged to Hemipedina (Diademopsis) incipiens (p. 124). 
Till proof of any such relationship is forthcoming, the only safe proceeding 
is to describe the radioles separately, and to give them distinct names. 
«Cidaris» Meyert. 
(Pl. XIII, figs. 430—432). 
1845. Cidaris Meyeri A. v. Kitpstetx, Geol. Ostlich. Alpen, p. 270, pl. xviii, f. 4 a, b. 
1865. Cidaris Mayeri |sic] Kutpsr., syn. of C. flexuosa Muwst., G. C. LauBr, Denkschr. Akad. Wiss. 
Wien, Math.-Naturw. C!. XXIV, Abth. 2, p. 290. 
1900. Cidaris Mayeri |sic| Kuipst., E. K. Hesse, Neues Jahrb. f. Min. Beil.-Bd. XIII, p. 231. 
Diagnosis. — Peripheral or circumapical radioles with elongate shaft, 
circular in section, swelling gradually from the annulus to one-third or one half 
way down, then tapering gently to the distal end; solid, or with small axial lumen; 
surface smooth except for a delicate longitudinal striation (of circa 24 striae to 
1 mm.) which is rarely preserved; base small; acetabular margin crenelate ; 
annulus smooth, not projecting beyond proximal diameter of shaft; collerette short, 
marked with longitudinal striae which pass over the annulus. The length of the 
radiole (20—380 mm.) being taken as 100, the length of the base is 2°2 to 374, 
diameter of collar 7°6 to 8°8, greatest diameter of shaft 11 to 12. 
The above diagnosis, with its measurements, is founded on the holotype, 
i. e. the specimen figured by Kuipstem, and on the best of his paratypes. For 
discussion of these, see p. 226. 
Material from Bakony. — A single specimen referable to this species 
comes from the Cassian of Section VI, Veszprém. It is the proximal half of a 
radiole, and is 11 mm. long. The complete radiole must have been cigar-shaped, 
but slightly compressed, with a flatter face on one side, which is almost straight, 
and a rounded face on the other side, which is bowed. The sagittal diameter at 
the thickest part of the shaft is 2 mm.; the transversal diameter 2°2 mm. A white, 
