PLATYCRINID ZA. 739 
Type of the genus: Coccocrinus rosaceus (Roemer). 
Remarks.— Coccocrinus has close affinities with Culiococrinus Miiller, closer 
even than has been generally supposed. The former was described by 
Miiller as having only one costal, while he recognized two in the latter, and 
made this the principal distinction between the two genera. Specimens in 
our collection show conclusively that not only C. bacca, but also C. rosaceus, 
has two costals. The only difference in the calyx upon which a generic 
separation might be upheld, is that in Culicocrinus the disk ambulacra are 
completely subtegminal, while those of Coccocrinus are partly exposed. The 
disk ambulacra, which are indicated in our specimen of C. rosaceus, are very 
narrow, and composed of minute alternating pieces, but too small to be 
satistactorily represented in our figure 14 on Plate III. 
Coccocrinus bacca Roemer. 
Plate LXXV. Fig. 15. 
1860. F. Roemer; Silur. Fauna des Westl. Tenn., p. 51, Plate 4, Figs. 5a, 6, ¢. 
1881. W. and Sp.; Revision, Part IL., p. 60 (Proceed. Acad. Nat. Sci. Phila., p. 234). 
A small species. Dorsal cup bowl-shaped, wider than high, subpentan- 
gular from a basal aspect, and somewhat asymmetrical in its general form. 
Plates smooth ; the suture lines not grooved and frequently invisible. 
Basals large, forming a low, rounded, pentangular basin, provided with 
a small, circular facet for the reception: of the column. Radials a little 
wider than long, the sides nearly parallel, the median portions slightly 
curved longitudinally and projecting outward. Three of the radials of 
similar form and symmetrical, the two posterior ones of irregular outline: 
the limbs toward the anal side rising considerably above the level of those 
of the opposite side; radial facets occupying two thirds the width of the 
plates. Costals two, very short; the upper one axillary with obtuse upper 
angle. The interbrachial pieces as large as the two costals together; their 
lower ends resting within a small notch formed by the radials, the sides 
against both costals, and against the ambulacra, the truncated upper face 
against the orals. Four of the plates are equal and stand at the same level, 
their upper ends inflected; the posterior one is erect and elevated above 
the others. Anus excentric, at the top of the posterior interbrachial, which 
at its upper end bends longitudinally inward so that its sides meet and form 
asmall tube. The orals unknown. eee 
