PLATYCRINID^. 739 



Type of the genus : Coccocrinus rosaceus (Eoemer). 



Eemarks. — 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 O. rosaceus, 

 has two costals. The only difference in the calyx upon which a generic 

 separation might be upheld, is that in Gulicocrinus 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 

 satisfactorily represented in our figure 14 on Plate III. 



Coccocrinus bacca Eoemeb. 

 Plate LXXV. Fig. 15. 



I860, r. RoEMEii; Silur. Fauna des Westl. Tenn., p. 51, Plate 4, Figs. 5a, *, c. 

 1S81. W. and Sp. ; Revision, Part II., p. 60 (Proceed. Acad. Nat. Sci. Pliila.,'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. Eadials 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 

 a small tube. The orals unknown. " ^ 



