Crinoidea, Pentacrininae. 41 
and consequent decrease of radial ridge-groups ; the simpler, i. e. more specialised, 
syzygies, especially as regards the almost total atrophy of the crenellae, without 
any concentration of them, so that the syzygial suture-line is not crenelate. These 
characters are inconsistent with the view, which the smaller average diameter might 
suggest, that the specimens are the young of mut. major. 
The arrangement of the crenellae approaches that of «Pentacrinus» venustus, 
but the perradial crenellae are more distinct, and of course the cirri are quite 
different. The large crenelate areas and small petal-floors may be regarded as 
primitive. The peculiar curvature of the crenellae, with its resemblance to the seven- 
branched golden candlestick, has suggested the name candelabrum. 
Intercalation of fresh Columnals in Young. — Specimen o from 
Cserhat consists mainly of an epizygal and two internodals (fig. 70). The epizygal 
face is markedly lobate, but that of the internodal is between subcircular and sub- 
pentagonal. The diameter is 1‘1 mm.; the height of an internodal 1:0 mm.; the 
height of the epizygal 0°77 mm. ‘The great relative height of the columnals, due to 
the youth of the specimen, is, however, discounted by the fact that fresh columnals 
are being formed between them. They do not appear regularly all round, but that 
between the two internodals is in two lenticular masses, about 0°7 mm. high, on 
one side of the stem, while that above the epizygal is a smaller mass, 0°4 mm. 
high, on the other side. The joint-faces are obscure and do not seem to have a 
definite rosette. 
Preservation of Axial Nerves. — Specimen p, also from Cserhat, is 
perhaps the most interesting of all the Echinoderm fossils described in this memoir. 
It is a complete intersyzygium of subcircular section, with five internodals. The 
surface is pitted in places, possibly by some boring organism. The measurements and 
other details have already been given. 
The interest centres in the joint-faces. In the hypozygal (figs. 73,74, text-fig. 5 A) 
the lumen is somewhat quinquelobate, with interradial angles, and a diameter of 
0°77 mm. The calcite filling it is much darker than the stereom of the ossicle. In it 
are six specks, invisible when wet but conspicuously white when dry, arranged with 
one in the centre and the others regularly disposed around it. This system, which has 
a diameter of about 0°25 mm., is shifted a little from the centre of the lumen towards 
one of the angles, but the 5 surrounding spots appear to have been interradial in 
position. Some of the spots appear to be joined to the central one by a narrow band. 
It was obvious from the first that this system represented the central vascular axis 
and the five prolongations of the chambered organ as they are found in all living 
crinoids (see for instance P. H. Carpenter, Challenger Report, Stalked Crinoids, pl. 
XXIV, ff. 1—5); but if the five surrounding specks were to be regarded as the 
canals prolonged from the chambered organ, then their interradial position was 
perplexing. Indeed this fact threatened my argument as to the relations between 
the aboral nervous system and the base,* and with it the main division of the Crino- 
idea into Monocyclica and Dicyclica.** 
* See «Third Notice of Wachsmuth & Springer’s Monogr.» Geol. Mag., dec. IV, vol, V, pp. 
422—426; Sept., 1898. 
** See BaTHer, «The Echinoderma» pp, 104, 111, 142, Vol. Ill in «Treatise on Zoology» ed. 
E. R. Lankester; 1900. 
