RHODOCRINID&. 229 
plates of the other areas. Anal opening excentric, directed upwards, placed 
within a large protuberance, composed of rather large plates. Ventral disk 
convex, depressed at the interradial spaces, and constructed of small, irre- 
gular, convex pieces without definite arrangement. 
Horizon and Locality. — Kinderhook group; Le Grand, Marshal Co., and 
Burlington, Towa. 
Types in the Museum of Comparative Zodlogy at Cambridge, and in the 
collection of Wachsmuth and Springer. 
Remarks. — This species is nearest allied to R. Kirbyi, from which it is 
distinguished by its more globose form, more slender arms, by the ridge- 
like series of anal plates, and the absence of interaxillaries. In the Le Grand 
beds this species is readily identified by its color, which is invariably light ; 
while all specimens of 2. Kirbyi are dark colored, and those of R. watersianus 
intermediate between the two. 
Rhodocrinus parvus S$. A. Mittrr. 
1891. 8S. A. Mitter; Geol. Rep. Missouri, Bull. 4, p- 39, Plate 5, Figs. 8, 9. 
Closely allied to R. nanus, but a somewhat smaller species and the calyx 
more depressed. Calyx subglobose, wider than high; the plates moderately 
convex, and covered in exceptionally well marked specimens by obscure 
ridges* passing from plate to plate; suture lines distinct. Infrabasals slightly 
extending beyond the column. Basals the largest plates of the calyx, bend- 
ing gradually upward. Radials nearly as large as the basals. The two 
costals together smaller than the radials, and frequently anchylosed. Dis- 
tichals five, very small, only the first a calyx plate, the succeeding ones free ; 
the upper axillary, and supporting two arms, which do not branch again. 
Arm openings arranged in pairs, each pair separated by a wide interspace. 
Arms delicate, composed of two series of deeply interlocking, cuneate pieces, 
the intervening sutures grooved. Pinnules not in contact laterally. The 
plates interposed between the radials very large, especially that of the anal 
side Interbrachials 2, 3, and 2, apparently also at the anal side. The 
ventral disk not exposed in the specimens. 
Horizon and Locality. — Lower part of Warsaw limestone; Booneville, Mo. 
Types in the collection of Mr. S. A. Miller, 
* We are led to believe that the ridges in Miller’s fizures are too distinct and misleading. In five speci- 
mens in the Missouri State collection with Miller’s label attached, there are no ridges at all, and the surface 
is smooth or slightly roughened. That this is not owing to the preservation is shown by the fact that the 
other parts are sharply defined. 
