246 Triassic Echinoderms of Bakony. 
species; but more minute comparison seems to show that these identifications, 
though not absolutely wrong, require some qualification. The general difference of 
facies, which was not unnoticed by Dr. Brom, seems to be due less to local con- 
ditions (whether of environment or preservation) than to a slight mutation in the 
direction of Raiblian species. I use the word ‘mutation’, in its original palaeonto- 
logical sense, to describe this change, because I regard it as correlated with a 
lapse of time. That is to say, Iam led to regard the Pachycardientuffe as between 
the true Cassian and the undoubted Raiblian. Since I came to this conclusion 
Professor Koken has discussed the age of the Pachycardientuffe very fully and 
places them in the Raiblian (N. Jahrb. Mineral, 1906, II, pp 12—19). So long as 
this is understood to mean Lower Raiblian, no objection need be raised on the 
score of the Echinoderms. 
The following are the more important references to the Echinoderms of the 
Pachycardientuffe in the present memoir. The so-called Pentacrinus propinquus, 
p. 54; Anaulocidaris Buchi, mut. nov granulata, p. 168; Cidaris scrobiculata, a 
slight mutation, p 183; C. decorata, p. 186; C. similis ?, pp. 190, 192; C. Haus- 
manni mut. nov. tofacea, p. 205; C. trigona, p. 223. 
In the paper just referred to, Professor Koken speaks of certain «Cidaris- 
Stacheln und Encrinus-Glieder» as «ganz indifferente» (p. 17). This is a reproach 
that should be removed by more careful collecting in the field and more minute 
study in the museum. 
2. Morphological. 
Whether for morphological or for systematic description, one of the first 
necessities is a precise and adequate Terminology. ‘Two causes have led me 
to discuss the terminology of various well-known structures at greater length than 
might have been anticipated in a work of this nature. First, the existing want of 
harmony between different writers, as regards both multiplicity of terms and differing 
applications of the same term. Secondly, the more detailed and minute description, 
necessitated by the fragmentary nature of the materials, involved an extension of 
the existing terminology in the interests of both precision and brevity. 
The structures for which a revised terminology has therefore been proposed 
are: 1. the Pentacrinine Stem (pp. 24—30); 2. the Test of the Regular Echi- 
noids, particularly as regards its ornament (pp. 59—65); 3. the Jaw-apparatus of 
the Regular Echinoids (pp. 129—130); 4. the primary Radioles (pp. 185—136). 
Turning now to questions of Anatomy, it will be recognised that no startling 
discoveries can be expected in material of this nature. There are, however, a few 
points of general interest. 
Among the Crinoids, the most striking discovery to my mind is that of the 
axial nerves in the stem of Jsocrinus candelabrum (p. 41). Now that they have 
once been noticed, it is probable that traces of these delicate structures will be 
found in other fossil crinoids, and that they will help us to unravel the relationships 
between Monocyclic and Dicyclic crinoids. 
In the Pentacrininae with their highly specialised stem, the occurence of truly 
hexagonal columnals is so rare, that the discovery of a hexagonal fragment in 
Isocrinus Hercuniae is worthy of note (p. 49, Pl. IV, figs. 106, 107). 
