124 Triassic Echinoderms of Bakony 
Hemipedina (Diademopsis) incipiens n. sp. 
(Plate IX, figs. 212, 213). 
Diagnosis. — A Diademopsis with two unequal meridional series of tubercles 
to each column of interambulacrals, the smaller series being adradial and having 
more than one tubercle to each plate; also with interradially situate secondary and 
tertiary tubercles, scrobiculate, and forming an irregular series. Ambulacrals about 
5 to an interambulacral. 
Material. — A fragment of an interambulacrum from the Raiblian beds of 
Cutting I on the Veszprém-Jutas Railway. 
Description of the Holotype. — The fragment comes from the adoral 
end of the interambulacrum, and consists of 5 plates of column }b, with a small 
interradial portion of the corresponding plates of column a. The plates are about 
four times as wide as they are high. The primary tubercles, one on each plate, 
form a main series, rapidly increasing in size as it passes from the peristome, but 
still remaining relatively small. The two main series of the interambulacrum almost 
meet at the peristome, but diverge rapidly so that on the 5th plate the tubercle is 
eccentric towards the ambulacrum. The mamelons are rather flattened; the platform 
does not extend much beyond them and has no distinct parapet. The bosses rise 
rather steeply from the scrobicules, which are confluent, and not clear, owing in part 
perhaps to a film of tenacious matrix. 
Between the main series and the adambulacral margin is a series of mamel- 
onate and perforate!secondary tubercles, of which about 5 correspond to the three 
larger primaries. These are small and do not greatly increase in size away from the 
peristome. As it nears the peristome, this series recedes from the adradial margin 
and approaches the main series. Along the adambulacral border appears to be a 
row of rather more closely set perforate tertiaries. Between all these tubercles are 
interspersed miliaries, but their arrangement is obscured by matrix. 
The interradial extra-scrobicular space is occupied by mamelonate and perforate 
secondary and tertiary tubercles, of which the former perhaps were disposed in a 
meridional series, numerically corresponding to the main series. The miliaries form 
fairly definite, though usually contiguous, rings round these secondaries, which are 
thus provided with definite scrobicules. This interradial series does not reach the 
peristome, but is separated therefrom by the convergence of the primary series. 
All the plates and fragments of plates are firmly united, and it is only on the 
inside of the test that the sutures can be distinguished at all, and even there not 
clearly (fig. 213). The convexity of the whole fragment is very slight, and this 
indicates that it came from the under surface of a rotular test. 
The adradial margin is almost vertical at the adoral end, but at its adapical 
end it slopes slightly downwards and inwards. ‘The denticles, which are rather 
irregular, indicate about 5 ambulacral plates to each larger interambulacral, and pass 
faintly over the inner edge. There is no ridge parallel to the margin. (Fig. 213). 
The peristomial border, measured from the interradius to the adradial margin, 
has a length of 3.3 mm. Thus the total length of one side of the peristome may 
be estimated at 6.6 mm.+say 1 mm. for the ambulacrum: total, 7.6 mm. Con- 
sequently the greatest diameter of the peristome would have been about 12.5 mm., 
and the diameter of the test cannot well have been less than 27.5 mm. 
