Systematic Res u Its. 
257 
venustus» has already been pointed out; their systematic relations are perhaps closest 
with Holocrinus (p. 22.). 
The other Triassic species heretofore generally referred to Pentacrinus are 
discussed (pp. 23, 30, 31): P. snbcrmatus and P. laevigatus are referred to 
Balanocrinus; P. amoenus, P. bavaricus, P. propinquus (including P. Braunii 
and P. Fuchsii), and P. tyrolensis are referred to Isocrinus. Of all these, only the 
last is found in Bakony, and then in somewhat modified forms, causing the erection 
of a new subspecies, I. tyrolensis major. Isocrinus propinquus is more fully dis¬ 
cussed on p. 54, and various fossils that have been referred to it are shown to 
differ in important features ; in fact the name Pentacrinus propinquus, as found 
in published lists, cannot be held to imply more than a medium-sized quinquelobate 
stem of Isocrinus. The new species from Bakony are the Cassian I. candelabrum, 
I. scipio, and I. sceptrum, and the Raiblian I. Hercuniae. 
Revised diagnoses of the Family Tiarechinidae and of its two genera Tiare- 
chinus and Lysechinus are published (pp. 67, 68), and the Family is referred to 
the Cidaroida with the Suggestion that it may be descended from the Lepidocentridae. 
In discussing the relationship of the Tiarechinidae, 1 did not think it necessary 
to consider any possible descendants of the Family, but tacitly accepted Dr. J. W. 
Gregory’s view that these forms constituted a specialised off-shoot from the main 
stem, adapted to the peculiar conditions of Triassic time, beyond which they did 
not persisf. Mr. A. Agassiz, in the passage previously referred to (p. 66), had at 
an early date (1883) compared Tiarechinus to the young stages of Podocidaris, a 
recent Arbaciid. In so far as Tiarechinus is an example of retarded development, 
with its ambulacral System permanently in a stage characteristic of immature Echin- 
oids, this comparison is illuminating; but, since it did not appear to involve any 
belief in a descent of the Cainozoic and Recent Arbaciidae from the Triassic Tia¬ 
rechinus, it had, I supposed, no bearing on the systematic position of the Tiare¬ 
chinidae. Since those pages were in type, however, Prof. L. Doederlein has empha- 
sized this comparison (1905, Zool. Anzeiger, XXVIII, p. 622 ; and Nov. 1906, 
«Echinoiden der deutschen Tiefsee-Expedition >, p. 183), and, while separating Podo¬ 
cidaris prionigera as a new genus Pygmaeocidaris, he says: «ich finde die Ähnlich¬ 
keit von Pygmaeocidaris .. . mit dem Tiarechinus aus der Trias so ueberraschend 
gross, dass ich nicht mehr daran zweifeln kann, dass diese beiden Formen nähere 
Verwandtschaftsbeziehungen miteinander haben müssen, bezw. dass Tiarechinus in 
die Nähe der Arbaciidae gehört». 
The points of resemblance, as stated by Doederlein, are: small size of test; 
relative size and Constitution of the apical System; Situation of the gonopores; 
restriction of primary interambulacral tubercles to the ambitus and adoral surface 
of the test; the presence of unpaired interambulacrals, Stretching from the peristome 
upwards along the interradius, and bearing unpaired main tubercles. 
The alleged points of resemblance may first be considered. Size of course is 
immaterial. The Constitution of the apical System in both Tiarechinus and Pygmaeo¬ 
cidaris is the normal one for Regular Endocyclic Echinoids ; such resemblance as 
obtains between the two genera depends merely on the large proportions of the 
System in Pygmaeocidaris, where, however, its diameter is 067 that of the test, 
while in Tiarechinus, according to Loven’s figures, it is 084. The Situation of the 
gonopores in Tiarechinus is not certain : two only of the genital plates bear round 
Resultate der wissenschaftl. Erforschung des Balatonsees. I. Bd. 1. T. Pal. Anh. 17 
