70 
Ti'iassic Echinoderms of Bakony. 
of the".change will be more readily comprehended after perusal of the following 
descriptions, which also correct an error in the generally received account (see p. 73.) 
l'riadocidaris persimilis 1 n. sp. 
(Plate VI. figs. 129—134.) 
Diagnosis. — A Triadocidaris with height of fest circa 0.7 diameter; with 4 
interambulacrals in a column, of which the ambital ones are higher than wide, while 
the space between their scrobicules is greater than the diameter of the scrobicules ; 
scrobicule circular, sunk; platform of boss higher than tops of scrobicular tubercles, 
distinctly wider than mamelon, flat; scrobicular ring of 14—15 secondary tubercles, 
with intercalated miliaries often radiately disposed; extrascrobicular surface filled 
with secondary tubercles equal to or slightly smaller than scrobicular tubercles, 
with interspersed miliaries. Ambulacra sinuous, with 18 ambulacrals to each ambital 
interambulacral, an inner alternating series of tubercles, with miliaries intercalated 
on the median line at the adoral end ; outer pores transversely elongate and mer- 
ging in a groove. 
Material.— From Cserhät (Leitnerhof) come 16 fragments, of which 3 (viz., 
a, b, h) contain ambulacrals as well as interambulacrals, while the rest are com- 
posed only of interambulacrals or fragments of the same. Seven out of the 16 have 
beeil selected as the basis of the following description, and are lettered a—g. Of 
these a, which consists of an almost complete ambulacrum and interambulacrum, 
is taken as holotype (figs. 131— 134). The remaining 9 are denoted by h — q. 
Front bed e 4 at cutting VI on the Veszprem-Jutas Railroad contes a fragmentary 
plate, lettered r and provisionally referred to this species. 
Three fragmentary interambulacrals, lettered 5, t, u, were collected by Prof. 
Laczkö in Giricses-Domb, Lower stratified Limestone. 
Seven imperfectly preserved interambulacral fragments, also from Cserhät, are 
doubtfully referred here. 
All these are of Cassian age. 
Description of the Specimens. — Specimen a (figs. 131, 133.) 
gives the height of the test as 10.2 mm.; and an ambital diameter, estimated by 
completing the pentagon, of 14.7 mm. The height is therefore circa 0.7 of diameter. 
Comparison with the rest of the material indicates that a was of normal dimensions, 
though a larger size was sometimes attained. Thus the largest interambulacral plate 
in a is 5.8 mm. high and 5.1 mm. wide. Specimen /is a plate 7.6 mm. high; specimen 
j a plate with a diameter of at least 7.1 mm.; and specimen 5 a fragment of a plate 
more than 9 mm. high. Assuming the measurements of the test to be proportional to 
those of its several plates, we arrive at the following minimal dimensions in millimetres 
for the complete tests of specimens — 
/ j s 
height 13'3 14*2 15-84- 
diameter 19'2 20'9 22 - 84 
Thus the exceptionally large specimen s would just about attain the diameter of 
the specimen of T. subsimilis figured by Laube (1865, pl. VIII b, f. 4), viz 23 mm. 
The height of that specimen is 14 mm. and the height of Münster’s holotype was 
1 Very like, to express the resemblance to T. subsimilis. 
