RETEOCRINID. 181 
Remarks. —The peculiarity that the smallest interradials are marginal 
and lie next to the radials and basals, instead of diminishing in size upward, 
as is usually the case, leads to the conclusion that these plates were intro- 
duced between some of the older pieces, and are secondary plates which 
cannot be homologized with the primary interradials of the Actinocrinide. 
The structure is well shown in our figure, Plate IX. Fig. 1/, which represents 
the inner floor of a fine specimen in which the arrangement of the primary 
interradials is very little disturbed, being 1, 2, 3, all of them isolated and 
surrounded by small supplementary pieces. We shall discuss this subject 
further in our remarks upon Xenocrinus penicillus and X. Baert. 
We have had no opportunity to examine the type specimen of Glyptocrinus 
cognatus S, A. Miller, in the collection of Dr. R. M. Byrnes of Cincinnati, but 
from the description and the figure we are strongly inclined to regard it as 
a large specimen of Reteocrinus Onealli, and not a variety of that species, as 
suggested by Miller. 
Reteocrinus magnificus (Miter). 
Plate IX., Fig. 2. 
1883. Gaurocrinus magnificus — 8, A. Mitten; Journ. Cincin. Soc. Nat. Hist-, Vol. VI., p. 280, Plate 11, 
Fig. 2. 
1885. Reteocrinus magnificus —W. and Sv.; Revision Paleocr., Part III., p. 94. 
1889. Gaurocrinus magnificus — 8. A. MILLER; North Amer. Geol. and Palont., p. 247. 
A larger species than Refeocrinus Onealli. Calyx subovoid ; section pen- 
tangular; the interradial and interdistichal spaces deeply depressed ; the 
radial ridges broad, flattened at their upper faces, and branching from the 
middle of the radials to adjoining basals. 
Infrabasals small, almost covered by the column. Basals of medium size, 
somewhat convex, their upper ends inflected toward the impressed inter- 
radial areas, the interbasal suture lines deeply grooved, and forming with 
the lower end of the radials a lozenge-shaped concavity. Radials a little 
narrower at the top than at the bottom. Costals two, narrow, as long as the 
radials, and without lateral extensions. Distichals very. variable in number, 
from two to fifteen, the three or four lower ones almost as large as the 
costals. When there are but two distichals, which is apparently exceptional, 
there is an additional bifurcation in the calyx; while in the other cases there 
is only one more bifurcation, which takes place in the free arms, and the 
second distichals support a very large pinnule. Arms stout, rounded and 
