; Dr. H. Woodward—On some remarkable Cystideans. 195 
of the column, which (as in Glyptocystites, Pleurocystites, and many 
others) was comparatively large at its attachment to the body, and 
was composed of narrow, somewhat compressed rings, to fit the 
flattened form of the base of the body. These rings appear to have 
diminished rapidly in size downwards, as in most other Cystideans. 
Specins.— Ateleocystites (Placocystites) Forbesii, De Koninck, 1869. 
Bull. Acad. Roy. Bruxelles, 2nde série, tome xxviil. pp. 
57-65, avee Planche. 
—_—_—____  —_——____ Geo. Maa. 1870. Vol. VII. p. 260, Pl. VII. Figs. 2-5. 
Ateleocystites (Placocystites) Hualeyi, H. Woodw. (non Billings), Gnon. Mag. 
1871, p. 71. 
Cee Smiae Cat. Camb. et Sil. Foss. Woodw. 
Mus. Camb. 1872, p. 128. 
General form of body oblong, compressed, especially at the lateral 
margins, which are sharply carinated ; convex on the posterior side, 
concave on the anterior side; having the lower angles rounded and 
the base somewhat deeply emarginated to receive the column. The 
body on each side composed of three oblong carinated marginal 
plates, placed one above the other, forming a * radial series” (Hall ; 
De Koninck). In addition to these, the posterior or convex side is 
covered by 13 small polygonal plates, and the anterior or concave 
side by 7 irregularly-shaped oblong plates, the three lower of which 
are by far the largest. The two lower marginal or ‘radial’ plates 
are longer than wide, and all three plates are so unequally folded 
over the sharply compressed lateral border as to give two-thirds of 
their breadth to cover the concave anterior side of the body, and 
only one-third to the convex posterior side. The lowest pair of 
carinated radial plates is strongly recurved, bending round the 
inferior margin of the body, and uniting with the small basal plates 
that encircle the articular surface for the column. 
On the concave anterior side, between these lowest pair of 
marginal plates, are seen two symmetrical oblong plates, about twice 
as high as wide; slightly broader at their lower half, their outer 
margins curved, their inner or median ones quite straight, their lower 
borders emarginated to receive the column. 
Resting upon the upper edges of these two plates is a single large 
oblong plate, the right-hand upper corner of which is truncated, 
giving insertion to a small and somewhat irregularly-shaped trian- 
gular plate; these plates are flanked by two large oblong marginal 
or radial plates, followed by two very much smaller ones resting 
upon them ; these latter serve to complete the superior angles of the 
body, and give insertion to two arms or tentacles, at their upper edge. 
Three small plates, broader than deep, form the summit of the body 
on the concave or anterior side. 
On the convex posterior side, the arrangement of the plates is per- 
fectly symmetrical, including the borders of the marginal or radial 
plates. The base supports a horizontal series of three plates, a 
broad median hexagonal plate, bearing a little to one side, a small 
circular plate covering the ‘ovarian’ aperture. The two lateral 
plates, placed next to the median hexagonal plate, encircle that plate 
