BATOCRINID^. 383 



ridges ; the margins of the plates beveled, so as to make the suture lines 

 quite distinct. 



Basals short, thickened around the lower margins and forming a hexa- 

 gon ; the lower face excavated. Eadials wider than long. First costals 

 quadrangular, their length equal to half their width ; the second pentan- 

 gular, often smaller than the first. Distichals 2X2} those of the upper 

 row wider and axillary, supporting 2X2 palmars. Arms eighteen to twenty. 

 Sometimes the anterior ray has but two arms, and in place of palmars an 

 additional row of distichals. Arm openings equidistant or nearly so. Arms 

 of medium length, cylindrical, decidedly tapering at their tips. Anal plate 

 a little narrower but longer than the radials, sustaining three and three 

 plates. The first plate of the regular sides quite large, followed by two or 

 three smaller ones, which are arched by the palmars. Ventral disk high, 

 conical; composed of irregular, convex pieces, which pass gradually into 

 the anal tube. The latter is central, stout at the base, but not very long. 

 Column tapering downward, the nodal joints projecting. 



Horizon and LocalUy. — Keokuk group ; Keokuk, Iowa and Nauvoo, Ills. 



I'ype in the Illinois State collection at Springfield. 



Remarks. — Adinocrinus simills Hall is identical with this species, except 

 that it has only two arms in the anterior ray. 



Batocrinus cantonensis M. and G. 

 Plate XXVII. Figs. 7a, h. 



1S90. MiLLEK and Guhlet; Journ. Ciucia. Soc. Nat. Hist., Vol. XIII. (June), Plate 6, Eig. 9. 



A rather small species. Calyx about one third higher than wide ; the 

 dorsal cup higher than the ventral disk, broadly truncate at the bottom, and 

 straight or slightly convex at the sides. Eadials and brachials extended into 

 well defined transverse angular nodes ; the interradial plates evenly convex ; 

 the plates of the tegmen and anal tube distinctly nodose. 



Base broad but short, the lower edge sharply angular and indented at 

 the suture ; the bottom flat, except the middle part, which is slightly exca- 

 vated. Radials considerably wider than long, their ridges directed obliquely 

 downward. First costals very short, linear. Second costals pentangular, 

 longer and wider than the first. Distichals 2X2; the upper ones axillary, 

 giving off a palmar from each side. The anterior ray generally has no pal- 

 mars, and in place of them an additional distichal. The palmars are in 



