LOWER HELDERBERG ROCKS. 
187 
Lepadocilnus geMiardi (Conrad). 
Plate YII. Pig. 1 - 20. 
SYNONYMES AND REFERENCES. 
Lepocrinites gebhardi : Conrad, Annual Report on Paleontology of New-York, 1840, p. 207. 
— — Vanuxem, Geol. Report of Third District of New-York, 1842, p. 117, f. 4. 
— — Mather, Geol. Report of First District of New-York, pp. 346 & 247, f. 4, 5. 
Body oblong, oval or ovoid, compressed at the sides, unsymmetrical, being 
much more gibbous on the lower part of the posteal or ovarian side 
than on the opposite; usually abruptly rounded above and obliquely 
subtruncate below. The basal series consists of four unequal plates, 
1, 2, 3, 4; the second series of five, 5, 6, 7, 8, 9; the third series of 
four, 10, 11, 12, 13; and the fourth or supraovarion of five, 14, 15, 
1G, 17, 18 : making the formula B, 4 + 5 + 4 + 5. The supraovarian 
plate extends downwards on each side, half enclosing the aperture : 
ovarian and circa-ovarian plates unknown. Plates of the summit un¬ 
known. A reniform depression and anal pore a little upon the left of 
the centre. 
Arms four, consisting of an anterior and posterior pair, which lie in 
shallow grooves along the rounded angles of the body, reaching nearly 
or quite to the base, and rising much above the surface of the adjoining 
plates; the anterior pair nearer to each other than the posterior pair, 
extending downward nearly to the base. The arms are composed of a 
double series of plates, each alternate one being similar. A range of 
minute ossicula extends along the centre of the groove between the 
plates of the arms, from which diverges a shorter range to the sinuosi¬ 
ties of the arms, where originate the fingers or pinnules. Fingers 
slightly alternate, but preserving the appearance of being in pairs or 
opposite; composed of a double .series of ossicula, closely interlocking 
at their contiguous wedgeform margins, and standing erect from the 
surface of the body, or lying close upon the arms and infolded in pairs 
beneath each other. Surface of plates granulate ; the granulations 
