84 
Tria.ssic Echinoderms of BaJcony. 
to select 36512, the original of fig. 15, as lectotype. The species is worthy of 
acceptance, but requires a new name, since C. Klipsteini was not available for 
Desor. 1 therefore propose Cidaris (seu Miocidaris) Cassiani noni. nov., in 
honour of the saint The third form known as Cidaris Klipsteini is represented in 
the colleetion of the Geologische Reichsanstalt, Wien, by three interambulacrals, 
two of which were figured by Laübe (1865, pl. IX, f. 7) under this name. Study 
of these specimens and of electrotypes of them in the British Museum (E4724) has 
convinced me that they are not of the same species as the type of Cidaris Klipsteini 
Desor, and are therefore to be called neither Miocidaris Klipsteini nor M. Cassiani, 
although they belong to Miocidaris. This form, however, needs no discussion at 
present, for, in the absence of evidence to the contrary, it must be assumed that 
Doederlkin would have interpreted M. Klipsteini by Klipstein’s figures rather than 
Laube’s. The genotype of Miocidaris, then, is M. Cassiani , of which the lectotype, 
from the Cassian Beds of St. Cassian, is British Museum No. 36512. 
J. Lambert (1900) retained the genus, but removed Cidaris subnobilis to 
Triadocidaris, and included Cidaris subcoronata , which Doederlein had placed in 
a separate section,' unnamed but numbered 5 and diagnosed thus: 
«Triassic Cidarids of moderate size with ribbed edges of the interambulacral 
lield fitting over [the edges of the ambulacral field]; primary tubercles very coarsely 
crenelate; pores yoked (?!)». 
Lambert (1900, p. 41) in discussing Miocidaris Amalthei says that the genus 
is «clearly characterised by the obliquity of its adambulacral sutures, and is dist- 
inguished from Triadocidaris by its crenelate tubercles, the arrangement of its 
circumapical tubercles, etc». 
The diagnosis now given (p. 83) differs from that of Doederlein only in the 
omission of the Statement that the scrobicules are slightly sunk and in the admission 
of elliptic as well as circular scrobicules. Further, whereas Doederlein makes no 
Statement as to the denticulation of the adradial suture, it is here asserted that it 
is denticulate as a rule. 
As regards the depression of the scrobicule, it was scarcely correct of Doederlein 
to describe it as slight when Klipstein definitely said that it was «sehr stark vertieft» 
in the original of his fig. 15 (the type of the genotype). It is true that in the plates 
incorrectly assigned by Laube to the same species, the depression is not so marked. 
But, apart from the correctness or incorrectness of the Statement, the character is 
not one that can safely be regarded as diagnostic of a genus. The species which, 
on other grounds, are herein referred to Miocidaris present every degree of Variation, 
from fiush to deeply sunk scrobicules. 
Still less does it seem possible to restrict a genus to sp>ecies with circular 
scrobicules. In Triadocidaris we have seen a continuous chain of species, with 
interambulacrals becoming gradually more compressed, and scrobicules contiguous 
and then confluent, and indeed single individuals presenting both distinct and contluent 
scrobicules. We may therefore expect to find similar Variation in Miocidaris. Under 
Triadocidaris an attempt was made to prove that the increasing ellipticity and 
confiuence of the scrobicules was a phenomenon of progressive evolution, correlated 
with an increase in the number of interambulacrals in a column. So far as that 
conception is correct, it must apply equally to other genera, and it results therefrom 
that a species with the ambital scrobicules elliptic and confluent cannot be the 
