el 
——= a at = Se Se a os 
= SS = a Se 
a we re nc aoe 
790 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
cup; the interradial spaces depressed and wider than usual in this genus; 
they are composed of four plates, of which the three of the first row rest 
upon the radials, their sides touching the distichals, the other being much 
larger and interposed between the radial dome plates. Orals very irregular | | 
in their arrangement; the posterior one strictly central, very large and i 
spinous; the others nearly flat, the position of the anterior one strictly inter- 
radial, while that of the two antero-lateral ones appears to be almost radial. 
The covering pieces enter the calyx after the first division of the ambulacra, 
and the two branches are separated by a rather large plate. The anal open- 
ing occupies the upper part of a well defined protuberance, a sort of rounded 
vertical ridge, which extends from the special anal plate to the posterior 
oral, and is surrounded by a deep groove. 
Horizon and Locality. — Upper part of the St. Louis group, at Tateville, 
Pulaski Co., Ky., associated with the preceding species. 
Zypes in the collection of Wachsmuth and Springer. | | 
Talarocrinus simplex (Suvum.). | 
Plate LDXXVILL. Figs. Sa, 0. 
1857. Dichocrinus simplec —Suumarp; Trans. St. Louis Acad. Sci., p. 74, Plate 1, Figs. 2a, 0. 
1858. Dichocrinus simpler — Hat; Geol. Rep. Iowa, Vol. I., Part L., p. 654, Plate 22, Figs. 12a, d. 
1882. Dichocrinus simplec —W. and Sr.; Revision Paleocr., Part IL, p. 84. 
cup generally a little higher than wide, widest at the basi-radial suture or 
a little above, somewhat cylindrical along the median portions, and gradually 
contracting toward the arm bases. Plates thick, and without ornamentation 
or other markings; suture lines distinct, but not grooved. 
Basal cup large, semiglobose, extending to fully one half the height of 
the calyx; the lower end slightly flattened, the central part excavated, 
A small species, the width of the calyx varying from 5 to 9mm. _ Dorsal . 
forming a narrow circular pit of considerable depth; the salient angles at the 
upper margin quite obtuse, the re-entering angles toward the anal plate and 
anterior radial comparatively sharp. adials slightly differing in form, some 
being wider than others, but all, as a rule, longer than wide and narrowest 
at the top. The superior faces of the plates are directed obliquely inward, 
and the ends are but slightly truncated; they are excavated to one half | 
their width by the facets which contain the costals and distichals. Anal plate ' 
generally wider at the bottom than the radials, but narrower at the top. 
