RHODOCRINID&. 245 
with the infrabasals and the extreme ends of the radials, forming a wide and 
deep inverted basin. Radials as large as the basals, a little longer than 
wide. Costals nearly one half smaller than the radials, both of the same size, 
and higher than wide. Distichals 2 x 2 in the calyx, nearly as large as the 
costals; the upper excavated to form the arm openings, which are large and 
circular. Appendages composed of single circular joints; the proximal ones 
in contact laterally. Their length and the construction of the arms un- 
known. Interradial spaces wide, elliptical; the plates between the radials 
smaller than the costals; the interbrachials arranged in rows of three and 
two plates, which decrease but little in size upwards. The anal interradius 
apparently not distinct. Interdistichals one. Column round, composed 
near the calyx of very short joints; the edges of the nodal ones knife-like. 
Horizon and Locality. —Lower Burlington limestone; Burlington, Iowa, 
and Sedalia, Mo. 
Type in the Museum of Comparative Zotlogy, Cambridge: 
Gilbertsocrinus fiscellus (Merx and Worrn.). 
Plate XVII. Figs. 2a, b, ¢, d. 
1860. Trematocrinus fiscellus— Merk and Worta.; Proceed. Acad. Nat. Sci. Phila., p. 383. 
1865. Gilbertsocrinus (Goniasteroidoer.) fiscellus —Mevx and Wortn. ; ibid., p. 167. 
1866. Gilbertsocrinus fiscellus —MbeExk and Wortu. ; Geol. Rep. Illinois, Vol. IT., p. 222, Plate 15, Fig. 5. 
1881. Ollacrinus fiscellus — W. and Sp.; Revision Paleocr., Part II., p. 219. 
1889. Goniasteroidocrinus fiscellus —S. A. Mrrter; North Amer. Paleont., p. 250. 
A small species, smaller even than G. reficulatus, which it resembles 
in general form; but the sides of the calyx are straighter, the basal con- 
cavity narrower, and the ridges upon the plates less conspicuous. 
Infrabasals very small, covered by the column. Basals hidden almost 
completely within the lower cavity, so that the radials and first interradials 
form the lower ring of plates visible from a side view. Costals as long as 
wide, and but little smaller than the radials. The second distichals support 
the free arms, of which the first joint is short and quadrangular. The arm 
openings of the same ray are placed closer together than in any other 
American species, and the tubes bordering the anal interradius are simple, 
with several interradial plates interposed between them; while those of 
the other sides, on the contrary, are united in pairs. Nothing further is 
known of the appendages and arms. Interradial areas arranged: 1, 3, 3, 3, 
3, 2; the lower plate somewhat larger. The anal side generally has five 
