40° Triassic Echinoderms of Bakony. 
joints, as one might expect from the small size of the interradial ligament-scars or 
petal-floors. The length and composition of the fragments is in fact due to struct- 
ure rather than to conditions of preservation, and may be regarded as a diagnostic 
character. 
Joint-faces. — Normal (fig. 68): the petal-floors are shortened by the encroachment 
of the raised central area, while they are not merely narrowed, but also ill-defined, 
through a similar encroachment of the crenellae, which die away into the floors. 
Sometimes the petal-floors appear depressed slightly, but sometimes, as in gq, they 
are slightly raised; in this respect also their instability is manifest. Of the peripheral 
crenellae the adradial are as usual the longest, and those of adjacent petals may 
meet on the periphery ; the crenellae radiate from a point about the centre of the 
petal-floor, and curve upwards towards the interradius as they near the periphery, 
thus diminishing the number of perradial crenellae; they number 5 to a petal in a 
columnar 1°6 mm. in diameter, and 8 to a petal in columnars of 2°3 mm. to 3:0 
mm. diameter; in g, with a diameter of 3°3 mm., an incipient 9th is seen on some 
of the interradii. 
The following are measurements of normal joint-faces in millimetres: 
J q 
Diameters. ie ee eee eee 30 33 
Length of sf] fies oe ee ares 15 ISH 
Length: ofr “rss ay cae oie on Ee 14 1°6 
From centre to end of petal-floor . . . 13 Pu 
Length of shortest crenella . . . . . 0-2 06 
Mengthpomlonpesin creme lla yaar a na 1:0 09 
Widthvotictenell ay iiss et ee O11 013 
Syzygial (figs 62, 65, 69, 73): in p the lumen of the epizygal appears to 
have radial angles, while that of the hypozygal at the other end of the fragment 
has interradial angles as usual. There is nothing else to add to the account in 
the diagnosis. 
The cirrus-facet (figs 61, 63, 64, 71, 72) abuts on, but scarcely indents, the 
hypozygal. In other respects it seems to have resembled that of [socrinus tyrolen- 
sis major, though the triangular pyramid is not so clearly marked. The joint-faces 
of the proximal cirrals also resemble those of that form, though the section is 
perhaps more circular, and the fulcrum a trifle stouter. The proximal cirrals appear 
to have turned downwards in /, but upwards in p. The following are measurements 
in millimetres of the distal joint-face of cirral 1: 
¢ & P 
Side yohicolumumen ureter aia 1.5 7 2°0 
Long diameter of facet. . . . 06 08 06 
Short diameter of facet. . .. 05 O07 06 
Relations of the Species. — In many respects the species resembles 
Isocrinus tyrolensis and its mutation major, but the points of difference are per- 
sistent. These are chiefly: less excavation of radial angles; greater absolute height 
of internodals, with a relative height twice as great; the narrow and _ indistinct 
petal-floors, correlated with longer creneilae; the curvature of the adradial crenellae 
