68 
Tri&ssic Echinoderms of Bakony. 
Genotype : T. princeps Neumayr. 
Revised diagnosis of Ly sechinus (based on the observations of Gregory). 
A Tiarechinid in which the single peristomial plate of each interambulacrum is 
succeeded by a horizontal rovv of tvvo plales abutting on the ambulacra and the oculars 
and this by a horizontal row of three plates, the outer ones abutting only on the 
oculars, and this hnally by a horizontal rovv of three plates. the outer ones abutting on 
the oculars and the genitals. 
Genotype: L. incongruens Gregory. 
7 iarechinus ? sp. 
(Plate VI, fig. 128.) 
Material. — A fragment, adherent to matrix, front the Cassian beds of Cserhät 
(Leitnerhof). 
Description of the Sp ec imen. — Height, 8.7 mm. Width, 6.5 mm. 
Along one margin are 12 rounded projections, each about 0.8 mm. wide, and 
rising slightly above the general surface At one end, the lower in hg. 128, thisjmargin 
seems to bend sharply round on itself, and there is a slight elevation at the angle. The 
remaining surface of the fossil is covered witli small pustules (? tubercles), irregulär in 
size and arrangement; and between them is a very fine granulation (? ntiliaries). 
R e 1 a t i o n s o f the Specimen. — It is with great hesitation that I refer this 
exceedingly obscure fragment to Tiarechinus, and 1 do so largely because there is no 
other form which it suggests either to me or to others who ltave kindly examined it. 
The absence of any appearance of definite sutures, even after prolonged treatment 
with glycerine and alcohol, is no evidence to the contrary; indeed a ntore vivid imagin- 
afion miglit interpret as sutures the markings or cracks which are to be detected with 
some difficulty. The general Ornament is sintilar to that on the interambulacrals and 
plates of the apical System in Tiarechinus. The interpretation provisionally suggested 
is that the fragment is the greater part of an interambulacrum, of which the adambula- 
cral border is preserved on one side (the right in fig. 128). The projections on this 
border are supposed to be more prominent tubercles alternating with the ambulacral 
plates. It is possible that the sltarp bend at the end of this border represents the 
adapical end of the ambulacrum, in which case the oral end has been placed uppermost 
in fig. 128. The curvature of the fragment is not unlike that shown in Loven’s figures 
153, 154; but if the specimen be Tiarechinus, it represents a form at least twice the 
size of any Tiarechinid hitherto described. 
Family: CIDARIDAE. 
Equals Section I of Cidaridae Duncan (J. Linn. Soc., Zool., XXIII, p. 26; 1889), as restricted by 
J. W. Gregory («Treatise on Zoology», ed. Lankester, III, p. 302; 1900.) 
Triadocidaris. 
1887. Triadocidans L. Doederlein: «Japanischen Seeigel», p. 39. 
1900. Triadocidaris Doed., J. Lambert: Bull. Soc. Sei. l’Yonne, LIII, p. 44. In addition to Münster 
1841, and Laube, 1865 , see also 
1887. L. Doederlein: N. Jahrb. f. Mineral. 1887, II, pp. 1—4, pl. i. 
1896. A. Tornquist: N. Jahrb. f. Mineral. 1896, II, p. 42. 
