BATOCRINIDZ2. 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. Radials 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 2 X 2 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. 
florizon and Locality. — Keokuk group ; Keokuk, Iowa and N auvoo, Ills. 
Type in the Illinois State collection at Springfield. 
Ltemarks. — Actinocrinus similis 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, b. 
1890. MitiEer and Gurizy; Journ. Cincin. Soc. Nat. Hist., Vol. XIII. (June), Plate 6, Fig. 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. Radials 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 2 2; 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 
