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BATOCRINID &. 403 
costals; followed by 2 X 4 palmars, except in the anterior ray, which has 
three distichals and no palmars. Arm facets large, projecting, directed out- 
ward. Arm openings arranged in groups; the interspaces between the rays 
twice as wide as the others, and slightly depressed. Arms eighteen; their 
structure is not known, but they were evidently large. Interradials one or 
two, very small, and arched by the palmars. Anal plate shorter and nar- 
rower than the radials; it is followed by three and one plate of nearly equal 
size, and by a narrow elongate piece at the arm regions. Ventral disk about 
as high as the dorsal cup, hemispherical, slightly bulging along the sides, the 
principal plates sharply nodose. Posterior oral strictly central, more spinous 
and larger than the four others; the radial dome plates arranged in groups 
of three over each ray. Anal tube excentric and very small: 
Horizon and Locality. — Lower Burlington limestone, Burlington, Iowa. 
Types in the collection of Wachsmuth and Springer. 
Eretmocrinus coronatus (Hatz). 
Plate XX XVII. Figs. 7a, b, ¢. 
1860. Actinocrinus coronatus — Hau; Suppl. Geol. Rep. Iowa, p. 28, Photogr. Plate 4, Figs. 1 and 2 
(1872, N. Y. State Bull. I.). 
1873. Evretmocrinus coronatus— Mrnx and Wortnmn; Geol. Rep. Illinois, Vol. V., Plate 10, Figs. 
1877. eee coronutus —S. A. MitteR; Amer. Palsoz., Foss., p. 66. 
1881. Eretmocrinus coronatus— W. and Sp.; Revision Paleocr., Part II., p. 173. 
1890. Eretmocrinus coronatus —S. A. MILLER ; North Amer. Geol]. and Paleont., p. 282. 
A somewhat aberrant form, in its general habitus approaching Dorycrinus. 
Calyx about as high as wide. Dorsal cup a little shorter than the ventral 
disk, broadly truncate at the lower end, where its diameter is equal to one 
half the width at the top; a little lobed at the arm regions. The plates are 
highly convex or nodose, the suture lines distinct. 
Basals stretched out horizontally, and sometimes hidden almost entirely 
by the overhanging nodes of the radials; they are deeply notched at the 
suture lines, forming a sort of trilobed plane, which in the central part is 
slightly excavated for the reception of a very small column. Radials moder- 
ately large, the two heptagonal ones with sharp salient angles, which fit in 
and rest within the lobes of the basal disk, and form a part of the lower 
surface. First costals quadrangular, twice as wide as long, narrower than 
the radials; the upper and lower faces straight. Second costals pentangular, 
generally a little longer than the first, and somewhat wider. Distichals two ; 
