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BATOCRINIDZ. 401 
Eretmocrinus leucosia (Hatt). 
Plate XXXVI. Figs. 7a, 6, ¢. 
1861. Actinocrinus leucosia —Hat1; Prelim. Descr. of New Crin., p. 1, and Boston Journ. of Nat. Hist., 
Vol. VIL. p- 261. 
1877. Batocrinus leucosia— 8. A. Mittrr; Amer. Paleeoz. Foss., p. 67. 
1881. Hretmocrinus leucosia — W. and Sr.; Revision Paleoer., Part I., p. 178. 
1883. ‘Eretmocrinus leucosia—S. A. Mitter; Amer. Paleoz. Foss. (Second Hdit.), p. 282. 
Syn. Doryerinus confragosus 8. A.Mittur, 1891; Geol. Surv. Missouri, Bull. I., p. 34, Plate 5, Figs. 
12 and 13. 
Syn. Batocrinus Blairi 8. A. Miter, 1892; Adv. Sheets 18th Rep. Geol. Surv. Indiana, p. 39, 
Plate 6, Figs. 7-10. 
Of the type of Hretmocrinus corbulis, but a larger species. - Calyx as high 
as wide, in large specimens somewhat wider; the rays slightly lobed at the 
arm regions, and grooved at the anal side. Dorsal cup broadly truncated at 
the base ; the sides uniformly spreading from the top of the basals, forming 
a straight or very slightly concave line to the bases of the arms. Plates 
moderately convex, without ornamentation, the suture lines grooved and 
quite distinct. 
Base short, projecting outward, and forming a salient, trilobate rim with 
sharp lower edges; the lower face perfectly flat except in the median part, 
which to one third the diameter at the bottom is slightly excavated; the 
axial canal large for this genus, and pentangular. Radials large, once and 
a half as wide as long, the upper face concave. First costals quadrangular, 
and small as compared with the radials; the second wider and pentangular, 
unless they are touched by the second row of interbrachials, which is excep- 
tionally the case. Distichals two, short; followed in four of the rays by two 
exceedingly short, transverse palmars, which support the arms; in the ante- 
rior ray, which has no palmars, directly by the arms. Arm facets very large, 
directed slightly upwards, and arranged in groups. The interspaces between 
the rays considerably wider than those between their subdivisions, and 
somewhat grooved, especially at the anal side. Arms eighteen, massive, 
long, incurving, and biserial from the calyx up; they are given off in pairs, 
and the two arms of each pair are suturally connected to the height of the 
third arm plate. For quite a distance from the calyx, the arms are evenly 
rounded at the back, but they grow flatter toward the tips, and increase 
some little in width. The arm plates are moderately short, and every fifth 
piece in both series is provided with a lateral spine. The spines near the 
calyx are quite short, but those in the upper regions attain a length of 4mm. 
51 
