262 Wachsmuth and Springer—Silurian Crinoids. 
ridges on the succeeding series of piates. The plate of the 
azygous side has three ridges passing upward; one from the 
center to become continuous with a ridge following the median 
part of the azygous interradius; the remaining two, which are 
directed obliquely, meet with similar ridges on the adjoining 
plates of the third order. The depressions between the ridges of 
the plates of the second order extend slightly to the plates of the 
first and third order; they are deep, especially the Jarger one at 
the azygous side, which has a depth of # of a line. The platesof 
the third order, which alternate with those of the second, are 
radial in position, and support in an upward direction a row 0 
other plates with strong, rounded, arm-like ridges, which in 
the specimen resemble closely arm plates, as which they were 
described by E. Billings. They are, however, evidently radials 
with elevated ridges, similar to the primary radials of /. 
O' Nealli Hall, which, like these, were connected laterally by 
interradial plates, and formed a part of the calyx. This is indi- 
cated by the numerous stellate pieces interspersed between the 
ridges, which in all probability represent interradial plates, of 
which only the elevated central portions are exposed to view, 
while their depressed margins are obscured by matrix. These 
stellate pieces are continued as high as the third plate of the 
secondary radials, and I have observed one within the axis of 
the first bifurcation to the left of the azygous series, thus indi 
cating that the body in this species is not confined to the three 
lower angles of the plates, as suggested by E. Billings, but that 
it extended to the secondary radials. 
“So far as the imperfection of the material will admit of com- 
parison, there is a strong resemblance between Releocrinus stel- 
laris and Glyptocrinus O’ Nealli Hall, which extends not only to 
the arrangement and form of first, second and third ranges of 
plates, but to the entire radial and interradial series, in vieW of 
which, and in the absence of any points of more than specific 
distinction, I am led to think the two forms cougeneric. 
‘In addition to the two specimens on which these remarks 
have been founded, and to those figured in Pl. 9, Dec. IV; 
G. 8. C., there is in the G. S. C. collection a flattened specimen, 
showing the side opposite to that shown in fig. 4a (loc. cit.), but 
wanting the first three ranges of plates, leaving the identity of 
the species not quite positive. This specimen (fig. 8, infra), 
has the interradial series more clearly and fully shown, and 1s 
filled with stellate pieces as high as the third secondary radials, 
below which they are interspersed with smaller and flatish 
plates, which grow smaller above, and disappear either lost 1m 
the matrix or through preservation. At one point at least, 
these smal] plates are seen to be continued with the arm pieces; 
they may represent the vault, and if so, this is another potant 
of resemblance to Gi. O' Nealli Hall.” 
