18 
Triassic Echinoderms of Bakonv. 
Trochita sp. 
In the museutn of the Hungarian Geological Institute is a columnal from Felsö 
Eörs, registered 10. 52. 1870, and said to come from Recoaro Kalk (Muschelkalk). 
It is labelled Encrinus [i. e. Dadocrinus\ gracilis, but the joint-face does not present 
the usual characters of Dadocrinus (vide infra). 
The columnal is barrel-shaped. The joint-face shows a small pentagonal lumen 
surrounded by a raised, rugose, flattened area, of which the rugosities merge into 
rather obscure radiating ridges, forming a circle within that of the peripheral crenellae, 
with which they are not continuo.us, although they appear to equal them in number, 
namely about 25. The peripheral crenellae are not deeply notched at the margin as 
in Dadocrinus. The mean diameter of the joint-face is 6'3 mm. 
PENTACRINIDAE. 
For definition, see Bather «The Echinoderma» p. 182; vol. III in «Treatise 
on Zoology», ed. E. R. Lankester. The primitive columnals, resembling those of 
Dadocrinus and Holocrinus, are dealt with first. 
Dadocrinus. 
1847. Dadocrinus H. v. Meyer: N. Jahrb. f. Mineral. 1847, p. 575. 
1851. » H. v. Meyer: Palaeontographica, I, p. 266. 
1887. » A. v. Koenen: Abh. K. Ges. Wiss. Göttingen, XXXIV, Phys. Kl. I, p. 5. 
References to most of the previous literature are given by von Koenen. The 
genus was for long confused with Encrinus, and has only gradually won acceptance. 
Flence its columnals have, it is probable, often been figured as those of Encrinus , 
and this increases the difficulty of distinguishing between the two. The best figures 
are those given by Kunisch (Zeitschr. deutsch, geol. Ges. XXXV, pl. VIII, f. 6 a — e ; 
1883), but these are only of natural size. A few joint-faces, probably belonging to 
the genus, are represented, some enlarged, by v. Meyer (1851, pl. XXXI, ff. 11, 12, 
15, 16, and perhaps others). Between columnals from the distal end of the stem 
of Dadocrinus and many columnals of Encrinus the figures show no difference 
except that of size. The extreme forms, however, as in Kunisch, f. 6 a and e, have 
not, so far as I am aware, been paralleled in Encrinus. 
The normal type of joint-face, as exemplified in a slab labelled D. Kunischi 
from Sacrau near Gogolin, Silesia, (Brit. Mus., E 6078), presents a lumen relatively 
larger than in Encrinus (being 0'3 mm. in a columnal of 1'6 mm. diam.), sur¬ 
rounded by a smooth raised area, which may be circular or irregularly pentagonal 
with interradial angles. Ridges radiate to the periphery from the outside of the central 
area, with which their tops are on a level and often continuous, so that the grooves, 
which are clearly marked and increase in depth towards the periphery, appear as 
though notched in the rim of the columnal. Sometimes, however, the central area 
is separated from the ridges by a groove, which may be narrow or wide, and is 
concentric with the periphery. The number of ridges in the cylindrical portion of 
the stem usually comes within the limits 8—20 mentioned by Kunisch, whose fig. 6 c, 
