I 4 il 
PALAEONTOLOGY OF NEW-YORK. 
one elongated and very unequally five-sided; the lower angular ex¬ 
tremity resting one side against the long basal plate of the concave 
side, and the opposite shorter side resting upon the sloping edge of the 
adjoining basal plate of the convex side. The second radial plates rest, 
one side against the lateral margins of the large central plate of the 
concave side, and the opposite sides adjoin the plates of the convex 
side; thus, with the base and summit, giving one of those plates an 
irregular hexagonal and the other a heptagonal form. Third radial or 
• angular plates heptagonal. Fourth radials unknown. 
Column unknown. 
This very anomalous form does not correspond in structure with any described 
species of eystidian or crinoid. The body is in form like some of the ovoid cystidians 
or crinoids cut longitudinally through the centre; and a little depressed on that 
side, with strong bent plates at the angles. The arrangement is distinctly in four 
series; the two lateral or angular plates corresponding, while the posteal and an teal 
series are very unlike in form, number and arrangement. The summit is broken 
off; so that the organs of mouth, ovarian opening, etc., remain undetermined. 
There are three plates preserved in each lateral series; and there was evidently a 
fourth, which probably supported spines similar to those observed in the other 
species, and which seem to be the only representation of arms or tentacula in this 
form of eystidian. 
The specimen figured has suffered no distortion, and the figures represent no more 
of the structure than can be seen distinctly. The basal range of plates on the posteal 
side are only partially preserved, and are described in part from the form of the 
spaces remaining, and from the corresponding parts in the other species where well 
preserved. 
Fig. 1. Anteal or concave side, showing the deeply arched or crescentform base with the 
succeeding plates. 
Fig. 2. Posteal or convex side, showing‘form and arrangement of plates. 
Fig. 3. Lateral view of the same specimen. 
Fig. 4, Diagram illustrating the structure of the body, showing the deep indentation for the 
insertion of the column : a, plates of the anteal or concave side ; p, plates of 
the posteal or convex side ; r, r, the lateral or radial plates, which are shaded 
to indicate the abrupt angles, one part of the plate serving to make up the 
convex and the other the concave side. 
Geological position and locality. In the Oriskany sandstone : Cumberland, Md. 
