202 ; __ Triassic Echinoderms of Bakony. 
Quenstept (1875, Petref. Deutschl. Ill, p. 194) referred C. Hausmanni to 
C. dorsata, but the radioles figured by him (pl. Ixviii, ff. 69—71) do not seem to 
be the true C. Hausmanni; they are larger and have irregular pustules. 
Hesse (1900) was the first to place the species on a secure basis by showing 
that its micro-structure was peculiar; to the details of this we shall return later. 
Brom (1904) stated that the radioles were common in the Pachycardientuffe 
of the Seiser Alp; but, as will be shown later on, these specimens differ in several 
respects from the Cassian forms, and are best regarded as a mutation of Lower 
Raiblian age, for which I propose the name fofacea. For the present it will be 
convenient to exclude this mutation, and to consider more closely the radioles of 
Cassian age under the name 
«Cidaris» Hausmanni typica. 
(Pl. XU, figs. 367—369 & Pl. XVI,. figs 448, 449.) 
Diagnosis. — C. Hausmanni of larger size, the average length being 
6 mm.; ridges well-marked and reaching the distal end of the shaft, with inter- 
vening grooves about as wide as the ridges, pustules usually distinct and rarely 
quite obsolete; base markedly oblique to the main radiole-axis. 
Lectotype, type-locality, type-description same as for the 
species. ‘ 
Description of Specimens from St. Cassian. — From a number 
of specimens in the British Museum apparently belonging to this species, I have 
selected eight, which certainly belong to it, for the study of the external form 
(E 9510—E 9517), and a ninth of similar appearance for the study of the micro- 
structure (E 9518). Specimen E 9515, though not quite complete distally, is figured 
(Pl. XU, fig. 367), as it shows the ornament and the base very clearly. Measure- 
ments in millimetres and other details are given in the following table: 
Register Number. . . . E9510 E9511 E9512 E9513 E9514 E9515 E9516 E9517 
Shape 2.0. 0. ss » FED quetfonaefestfonn fmm» 00202 peepee ten in ae 
Wenigth 3 iighlce ty eos ERA 49 55) 59 66 70 73 76 
Greatest diameter . . . s ie a oe ae = go me deh 
r 2°4 159.9) BD 30). 24 
Diameter at annulus . . 11 10 1°4 10 16 1°5 Se 12 
Number of ribs in a width 
of 1mm... . . 3—3'5 25—3 25—3 25—4 2—3 2—38 2-3 2 
Number of pustules in a 
length of 1 mm... 45 3—5 3—4 3—4 ? 3—3'5 3—4 3—4 
The shapes compose a continuous series: thin fusiform, swollen fusiform, 
pyriform, globose, with all intermediate stages. 
When two diameters are given, the first is that of the sagittal plane determined 
by the obliquity of the base. Whenever a difference can be detected, the sagittal 
diameter is greater than the transversal; in this respect the species differs from 
most, if not all, others discussed in this memoir. Usually the sagittal plane is also 
the dorso-ventral plane, but we cannot prove that it is so in this species. 
