Crinoidea, Pentacrininae. 
37 
Relations of the Variety. — In the far greater lobation, the number 
of crenellae, the structure of the cirral joint-face, and minor points, these specimens 
present some obvious differences from both I. tyrolensis and its mutation major. 
In other characters, however, the resemblance is such that, if a and b alone were 
concerned, I should suppose them to come from the proximal part of the stem of 
I. t. major. But the number of internodals in e and f bars those specimens at any 
rate from such an interpretation. Only the accumulation of a larger number of 
specimens will enable us to decide whether this form represents a growth-stage, an 
individual Variation, or a local variety of I. tyrolensis major — or possibly an indep¬ 
endent mutation from I. tyrolensis, indicating divergent evolution. 
Isocrinus tyrolensis var. ß 
(Plate H, fig. 54.) 
Material — A fragment consisting of three internodals, of which one is 
perhaps a hypozygal, from Cutting I on the Veszprem-Jutas railway, is doubtfullv 
referred to this species. It is somewhat weathered, but not rubbed. Raiblian. 
Description of Specimen. — Section scarcely lobate, rather sub-concavi- 
stellate. 
Side-faces almost straight. Suture-line slightly depressed, and clearly crenelate 
all round. Ridges pass from the crenellae over the side-face, more markedly than 
in the holotype of I. tyrolensis, but, since the crenellae on one joint-face of a 
columnal do not quite coincide with those on its other face, these ridges are neither 
regulär nor strictly vertical. They have perhaps been brought out by weathering. 
A clean joint-face has been exposed by breaking away one of the columnals. 
Lumen minute, area and petal-floors flush, the latter not elongate. Radial ridge- 
groups consist adcentrally of small granules, but the perradial crenellae, about 4 in 
number, rapidly increase in length as they near the periphery and are sometimes 
curved in such a way that the distal gables, instead of being A-shaped, approach 
a A shape (lambdoid). Peripheral crenellae about 8 to a petal 
Measurements of a columnal: Diameter, 3.0 mm.; height, 0.8 mm.; r 1.4 mm.; 
ratio, — diameter: height:: 100:26.6. 
Relations of the Variety. — The flush area and petal-floors constitute 
the chief differences from the norm of I. tyrolensis major. 
Isocrinus tyrolensis var. 7 
(Plate II. figs. 57—60.) 
Material. — There are seven stem-fragments from beds a-b of Cutting IV 
on the Veszprem-Jutas Railway, and one from bed b 1 of the same cutting. Raiblian. 
Description of specimens. — All these closely resemble both the 
typical form of the species and the norm of mut. major, except in their smaller 
size, as shown by the following measurements in millimetres. 
Diameter ............. T2 T3 T5 1*7 T 8 T9 2T 2T 
Height of internodal. 0‘5 0'6 0‘45 0‘36 0’6 0'44 0'43 0‘5 
» » epizygal . 0'4 0’5 0‘4 0'4 0‘65 0‘5 0'4 0‘8 
Diam.: 100:: height of internodal: 4 T0 46‘0 30‘0 2 T0 33'0 23’0 20‘0 24’0 
