102 
Triassic Echinoderms of Bakony. 
Suggestion of Laube (1865, p. 295). But this action has not been based on any 
study of the unique holotype, for that unfortunately is lost. It may therefore be a 
valid objection that the original diagnosis of Cidaris Admeto by Braun in Münster 
(1841, p. 40), differs from that of C. regiüaris in the following points: interambul- 
acral plates 6 or 7, instead of 10 to 12; extra-scrobicular Ornament of close-set 
secondary tubercles not much smaller than those of the scrobicular ring, instead 
of a fine granulation. 
Eodiadema ? sp. indet. 
(Plate VIII. figs. 190, 191). 
Material. — A fragment comprising four plates from the adapical end of an 
interambulacrum ; from the Cassian horizon of Cserhät, Leitnerhof. 
Description of the Specimen. — The plates are relatively high and the 
interambulacrum relatively narrovv. Three plates bear well-developed main tubercles, 
while the fourth has only an incipient tubercle. The main tubercle bears a relatively 
large, almost hemispherical mamelon, vvith very small Perforation; this is supported 
on a low boss, of vvhich the platform has about 16 crenellae. There is no scrob¬ 
icular depression, but the boss seems to rise directly from a field densely covered 
with miliaries. The adradial margin is cle^irly scolloped, and bevelled to a thin edge 
on the inner surface, which bears about 5 slight denticles to each interambulacral. 
Relation s of the Specimen. —It is the nature of the extra-scrobicular 
Ornament that suggests the reference of this fragment to Eodiadema. The relative 
height of the plates is due to their adapical position. The flexible adambulacral 
suture has not, it is true, been described in any species assigned to Eodiadema, 
but it may have existed in the earlier ones, especially at the adapical end, which 
is the last region to be affected by the change to a rigid suture. 
Suborder: DIADEMINA. 
The interambulacral plates which remain for consideration present many diff- 
iculties. They fall into three species, two of which certainly and the third probably 
still possessed loose and to some extent imbricate adradial sutures. They cannot 
however be kept in the «Streptocidarinae» owing to the nature of their tuberculation, 
which effectually removes them from the Cidaridae. A place therefore must be found 
for them among the Regularia Ectobranchiata. Since the tubercles are perforate and 
non-crenelate, search will most profitably be conducted among those genera which 
Duncan (1889) placed in his Family Diadematidae, Gregory (1900) in his Suborder 
Diademina, and Lambert (1900) in a Subfamily Pedininae 1 and Tribe Orthopsinae. 
In none of these has such a loose adradial suture been described, at all events in 
the adult stage, and it might seem preferable to erect a new genus or new genera 
for these Triassic species without more ado. Some isolated interambulacrals bearing 
the name Hemipedina Bowerbanki in Wright’s handwriting, and now preserved in 
the British Museum (E 3299), do however show traces of the denticles. In one of 
the fragments the adradial edge is exceedingly thin, and the denticles faintly visible 
on the inner surface; this was apparently from the adapical region. In the other 
1 Not the Same as the similarly named Subfamilies and Families of Duncan and Gregory res- 
pectively, but more the equivalent of Farn. Pedininae in Dhlage and Herouard (1904). 
