Echinoid Tests. Cidaroida. 91 
the meridional diameter of the plate is 2.6 mm., that of the scrobicule is a trifle 
less. The transverse diameter of the plate is 6.7 mm., and that of the scrob- 
icule 2.7 mm. ; 
The whole extra-scrobicular surface is irregularly crowded with rather small, 
obscurely mamelonate, imperforate secondary tubercles, interspersed with a few 
smaller tubercles and miliaries. In the third plate of specimen a, the adradial tract, 
which is about 1.2 mm. wide, and 2.1 mm. high, bears 9 secondary tubercles ; 
the interradial tract is incomplete. In b, the plate whose measurements are given 
above has an adradial tract 1.2 mm. wide, and an interradial tract 2.8 mm. wide. 
In neither a nor 6 can any of the secondary tubercles be distinguished as scrobi- 
cular; but in 6 the number of secondaries bounding the scrobicule on the right 
and left is about 5 on each side. 
The adradial margin, which is exposed in a alone, is bevelled to a sharp 
edge on the fourth plate, but comes to lie at a less sharp angle as it approaches 
the peristome. It bears 4 or 5 strong denticles on each plate. 
The peristomial border is thickened, but bears no internal processes. 
Relations of the Species. — This is distinguished from the Cassian 
species of Miocidaris by the confluent or closely contiguous scrobicules, in which 
respect it resembles the Permian species referred by Lampert to Eotiaris. From 
them again it differs in its tuberculation and in the stronger denticles. 
Miocidaris planus’ n. sp. 
(Plate VII. figs. 157—159.) 
Diagnosis. — A Miocidaris in which the interambulacral plates are nearly 
twice as wide as high, with scrobicules contiguous, flush, surrounded by about 18 
relatively small, distinctly mamelonate, imperforate scrobicular tubercles; with plat- 
form of main tubercle nearly twice as wide as the mamelon and marked by about 
18 crenellae continued as folds down the side; with miliaries coarse, close-set, and 
irregular in size and arrangement; with adradial margin faintly denticulate. 
Material. — (a) Holotype, an interambulacral plate ; (b) a portion of another : 
both from the Raiblian beds of Jeruzsalemhegy. 
Description of Holotype. — A large plate, irregularly pentagonal, with 
its adradial margin oblique to the transverse margins. Diameter: transverse, 12 mm.; 
meridional, 6.5 mm. 
The main tubercle occupies the greater portion of the plate, and projects 
2 mm. above its surface. Its circular mamelon has a meridionally extended per- 
foration, a depressed hemispheroidal summit, and long neck slightly undercut. The 
diameter of the mamelon is 1.8 mm.; that of the platform, 3.2 mm. There are 18 
strong crenellae, and no parapet. The slopes of the boss are straight, and are 
steeper on the adapical and adoral sides than on the others, so that the base of 
the boss has a transverse diameter (circa 4.7 mm.) greater than its meridional 
diameter. The flush scrobicule itself has a transverse diameter of 7.2 mm., and a 
meridional diameter of 5.3 mm. The scrobicular ring, however, is not elliptical, but 
consists of an almost straight upper and lower tract adjoining the transverse mar- 
gins of the plate, a slightly curved radiad tract, and a more curved interradiad 
' Level, in allusion to the flush scrobicules. 
