256 Triassic Echinoderms of Bakony. 
the Liassic Diademopsis; it is known also to occur in the «Cidaris» olifex, C. amal- 
thei, and C. arietis of QuENSTEDT, species which on other grounds appear to approach, 
if they do not actually belong to, the Diademoida. This fact, then, suggests forcibly 
a descent of the Diademoida from the primitive streptosomatous Cidarids of the 
Permian and the Trias. 
As regards the general shape and ornament of the interambulacrals, no definite 
statement can be made. In several early species of Hemipedina these plates fre- 
quently have a Cidarid appearance. There is, however, nearly always to be detected 
some trace of secondary tubercles (other than scrobicular), and there is correlated 
therewith an approach of the primary tubercles to the adradial margin, as well 
as a general widening of the plates. The fossils referred by various writers, 
including myself, to Mesodiadema have generally been placed in the Diademoida 
owing to this width of the interambulacrals, and the excentricity of their tubercles, 
rather than for any more fundamental reason. The reference to Diademopsis of 
the interambulacral fragment described on p. 124 is made on the same grounds, as 
well as on the still plainer evidence of serially arranged secondary tubercles. This 
remarkably interesting fragment, to whatever genus it may ultimately be referred, 
offers as convincing evidence as any other fossil herein described of an intimate 
connection with the Cidaridae, both in the denticulate adradial margin and in the 
remains of the interradial auricle. It further bears upon the view elsewhere expressed 
(p. 116) that Diademopsis arose independently of Hemipedina and probably at an 
earlier period. 
In short, then, we have seen that, whatever feature preserved in these fossils 
be taken, each shows a gradual progress from the Cidarid to the Diademoid plan 
of structure. The hypothesis that the Diademoida and the remaining Ectobranchiata 
were derived from the Cidaridae,-however improbable it may at first have appeared, 
seems now to have a firm foundation. 
3. Systematic. 
In this memoir there are described about 23 species and varieties of Crinoids, 
about 45 of Echinoids, and one Asteroid. The numbers cannot be given with 
precision owing to the doubtful nature of several fragments; further the number 
for Echinoidea is excessive, since the radioles are treated separately from the frag- 
ments of test. Of new species there are 6 in Crinoidea, 9 based on tests of Echin- 
oidea, and three based on radioles. The Crinoids fall into the Families Encrinidae 
and Pentacrinidae; the Echinoids into the Tiarechinidae?, Cidaridae, Acrosaleniidae ?, 
and Diadematidae (s. lat.). The material throws no particular light on the limits 
of the Families, and what bearing it has on their ordinal relations has already been 
discussed for the most part in the previous section of this summary. Here attention 
may be directed to a few of the results concerning genera and species. 
Under Encrinus will be found a discussion of various species, especially 
E. cassianus (p. 9), E. granulosus (p. 11), and E. silesiacus (p. 14). There seems 
to have been some confusion between the last-mentioned and E. radiatus Scuaur., 
and the latter is here regarded as an early stage of Balanocrinus (p. 16). 
The morphological importance of the stem-fragments known as «Pentacrinus 
