Crinoidea, Pentacrininae. 
43 
Isocrinus scipio n. sp. 
(Plate III, figs 77—89,1 
Diagnosis. — Transverse section varies from subcircular, through subpentagonal 
and quinquelobate, tu stellate; the last, however, being only in the syzygial region. 
The majority are slightly quinquelobate. Extremes of diameter observed, IT mm. 
and 27 mm. Height of internodals rather more than one-third their diameter in 
adult to more than four-fifths their diameter in younger stages; or diameter taken 
as 100, height is from 34 to 83 (average 57). Side-faces smooth, straight, slightly 
convex, or slightly concave, and sometimes with incipient radial pores ; interradial 
angles of epizygal swollen into rounded ridges, which rise towards the syzygy and 
thence die away into the hypozygal. Suture-line flush or slightly raised, crenelate 
all round, except at syzygies. Internodals usually 5, may be 4. 
Joint-faces. Normal: lumen minute, subcircular to pentagonal; central area 
very slightly raised, vermicular, reaching perradial crenellae, but not merging in 
them, occasionally indistinguishable, especially in smaller specimens; petal-floors 
flush, pyriform, with straight sides and semicircular ends; radial ridge-groups of 
one or two pairs, of which the adcentral pair may fuse into a relatively conspicuous 
radially directed ridge, while the components of the acentral pair either meet at an 
angle or are themselves fused with the ridge; peripheral crenellae 4 to 7 in a petal, 
according to size, usually 5, regularly arranged and differing but slightly in length, 
clean-cut and distinct. Syzygial: scarcely a trace of crenellae; convexities and 
concavities of the usual type, except that the hypozygal is often slightly concave 
interradially. 
Cirrus-facet at the truncated end of a subconical depression, which lies in the 
lower two-thirds of the epizygal and cuts into the hypozygal slightly; it is very 
slightly elliptical with a faint rim and broad fulcrum. Distal face of cirral 1 flush 
with columnar side-face, slightly transversely elliptical; rim distinct, may be doubled 
at upper margin; muscle-fields excavate; fulcrum just above centre, separate from 
rim, and tapering to centre, where the lumen lies below it. 
Material. — This is the commonest species at Cserhät (Leitnerhof), there being 
no less than 473 stem-fragments from that locality. There are also referred here 22 
stem-fragments from Veszprem, Giricses Domb, lower stratified limestone, and one 
doubtful crushed fragment, consisting of three columnals, from bed e of cutting VI on 
the Veszprem-Jutas railway. All these are of Cassian age. 
The description and measurements are based on 49 specimens selected from 
the Cserhät lot to represent the different diameters; and from these 11, lettered a 
to l , have been chosen for figuring. No single specimen shows all the diagnostic 
characters, but d is hereby selected as holotype. 
Description of Specimens. — The following measurements in millimetres 
are based on averages of the columnals: 
Diameter.. 
IC 
IC 
T2 
1-4 
1'4 
1-4 
1-6 
1-7 
17 
1-8 
Height of intern odal . . 
0-8 
0-9 
1*0 
0-9 
0-97 
IC 
0-83 
0-98 
1.05 
0-97 
Height of epizygal . . . 
— 
0-9 
1*0 
0-9 
ro 
ro 
0-9 
1*0 
0-9 
101 
Diam. 100, height. = 
72 
81 
83 
64 
69 
78 
52 
57 
61 
54 
