Echinöid Tests. Cidaroida. 
87 
on the outer limit of the bevel vvhich stops the plate next above it from sliding 
right over it. Similarly, of the interradial margins the adoral one is «nach innen 
abgeschrägt» and the adapical one «nach aussen». The correctness of this account 
depends on the meaning to be attached to «nach innen» and «nach aussen». Now 
Spandel goes on to say that the adradial margin of each interainbulacral is «nach 
innen abgeschrägt», and it is admitted by all that this faces inwards. Therefofe it 
would seem that, according to Spandel, the adoral transverse margin has a bevel 
facing inwards; but this is incorrect. On the other hand Spandel’s figures (pl. XIII, 
f. 4 a & b) are clearly meant to show that the convex adoral margin has a bevel 
facing outwards; and this is correct. We might therefore translate «nach innen 
abgeschrägt» as «with a bevel facing outwards», and suppose that in describing 
the adradial margin Spandel had written «innen» for «aussen» by a lapsus calami. 
Unfortunately the question is further complicated by the Statement that «an der 
äusseren Grenze der Abschrägung des oberen Randes liegt eine Leiste, u. s. w.»; 
for in his section across an interambulacral (pl. XIII, f. 2) Spandel has drawn this 
ridge on the outer limit of the bevel facing outwards, which we have just decided 
must be the adoral («untere») margin. 
The actual facts, as ascertained from an independent examination of specimens 
of Miocidaris Keyserlingi (Brit. Mus., El 119, El 121), may be thus expressed : 
Margin — 
adradial 
adapical 
adoral 
apicad- 
interradial 
orad- 
interradial 
Bevel facing — 
inwards 
inwards 
outwards 
inwards 
outwards 
Nature of 
suture 
transverse 
denticles 
ridge 
on inner 
margin, 
sometimes 
ridge 
on outer 
margin, 
usually. 
smooth 
smooth 
Essentially the same structure obtains in M. Cassiani, as observed in the 
lectotype and in Brit. Mus. E8552. It may also be seen in Miocidaris sp. (Brit. 
Mus. E8553) from St. Cassian ; in a plate of Miocidaris sp. from the Cassian beds 
of Cserhät; in Miocidaris planus from the Raiblian of Jeruzsälemhegy; and in a 
plate of Miocidaris sp. from the same horizon at Cutting I on the Veszprem-Jutas 
Railroad. Quenstedt (1875) does not mention it in M. amalthei or M. arietis, but 
if the plates are so cleanly isolated as his figures (pl. LXVII, ff. 3, 5, 6, 21, 55) 
imply, then the suture must have been a loose one. I have not observed the 
bevelling in M. verrucosus , but the material scarcely warrants an assertion of its 
absence. In M. subcoronata, however, the large plates have almost or quite vertical 
sutures, with only a faint trace of a median depression ; and this perhaps shows 
that Doederlein was right in separating this species from Miocidaris. 
The supposition that in all these species the bevel facing outwards is adoral 
rests partly on my own observations, partly on accepted Statements as to the 
imbrication in Echinoidea generally, and especially on the conclusions of A. Torn- 
quist in his excellent «Beitrag zur Kenntniss von Archaeocidaris» , in which genus 
the meridional imbrication of the interambulacrals is adapical. Just as the denticulate, 
overlapping, adradial suture of Triassic Cidaridae is only a stage in phylogenetic 
