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 Zoology, Cambridge. 



Gilbertsocrinus fiscelluS (Meek and Worth.). 

 Plate XVIL Figs, ^a, h, c, d. 



1S60. Trematoc.nmis fiscellus — Meek and Wouth. ; Proceed. Acad. Nat. Sci. Pliila., p. 383. 



1865. Gilbertsocrinus (^Goniasteroidocr.') Jiscellus — Meek and Wouth. ; ibid., p. 167. 



1866. Gilbertsocrinus fiscellus — Meek and Worth. ; Geol. Rep. Illinois, Vol. II., p. 222, Plate 15, Pig. 5. 

 1881. Oil acrinus fiscellus — W. and Sp. ; Revision Palseocr., Part II., p. 219. 



1889. Goniasferoidocrinus fiscellus — S. A. Miller; North Amer. Palseont., p. 250. 



A small species, smaller even than G. reticulatus, 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 ; tlie lower plate somewhat larger. The anal side generally has five 



