Echinoid Tests , Cidaroida 
89 
Miocidaris ? sp. indet. «. 
(Plate VI figs. 150—152.) 
Material. —- Two fragments, a large (a) and a small (b), of isolated inter- 
ambulacrals, from the Cassian beds of Cserhät, Leitnerhof. 
Description of Specimens. — ( a ) The larger fragment has a relatively 
small mamelon, vvith a transverse diameter of 1.3 mm., and a meridional diameter 
of 1.4 mm.; it is perforate, depressed hemispheroidal, vvith neck slightly undercut, 
resting on a vvide platform of 2.7 mm. diameter. The platform, which is marked 
by 13 crenellae, has vertical sides, from which the boss falls away in a straight 
slope of about 30° to the horizontal. The scrobicule is scarcely, if at all, depressed, 
and, since there is no trace of any scrobicular ring or extra-scrobicular Ornament, 
its diameter cannot be stated definitely. There may have been some interradial or 
adradial extra-scrobicular Ornament beyond the limits of the fragment; but one of 
the transverse margins is preserved and shows that there was no intertubercular 
Ornament, for the scrobicules were confluent. The face of this transverse suture is 
grooved, and the plate has here a thickness of 0.6 mm. (Fig. 152). 
(b) The smaller fragment has the same general characters. The diameter of 
the mamelon is 1.25 mm.; that of the platform, 2.5 mm. There are 15 crenellae. 
The meridional diameter of the plate is 5.3 mm. Only the transverse margins are 
preserved; of their sutural faces one, presumably the adapical, has a bevel facing 
inwards, while the other is grooved; the plate here is 0.6 mm. thick. (Figs. 150, 151). 
Relations of the Specimens. — In the absence of theadambulacral margin, 
the crenelate boss suggests a reference to either Miocidaris or Plegiocidaris ; but, 
since the transverse sutures indicate that the test was still flexible, one decides in 
favour of the former, streptosomatous genus. If the absence of Ornament is merely 
due to the loss of all the extra-scrobicular tracts, then the fragments may be merely 
the scrobicular portions of some species vvith confluent scrobicules, and therefore 
neither of the Cassian species hitherto described. The Permian species are out of 
the question. Compared vvith M. verrucosus, the present plates are twice the size 
of any belonging to that species, while the scrobicule is larger in proportion to 
mamelon and platform. It seems probable then that the plates belong to an unde- 
scribed species; but if they really were devoid of extra-scrobicular Ornament, the 
probability would be a certainty. Obviously, hovvever, such fragments do not warrant 
the establishment of a new species. 
Miocidaris sp. indet. ß. 
Material. — A fragment of an interambulacral from the Cassian beds of 
Cserhät, Leitnerhof. 
Description of the Specimen. — This consists of the mamelon, part of 
the boss and scrobicule, and parts of two adjacent scrobicular rings. The mamelon 
is depressed hemispheroidal with slightly undercut neck, and has diameters of 1 mm. 
and 0.85 mm. Its Perforation is extended in the direction of the greater diameter. 
Diameter of platform about 1.2 mm. Crenellae not very clear, and about 16 in 
number. Boss not very high, slopes with a gentle concave curve to the slightly 
sunk margin of the scrobicule. If the fragment of the scrobicular ring were com- 
pleted so as to form a circle, and if the tubercles continued of the same size and 
