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574 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
length provided with short hooks, Regular interbrachials: 1, 2, 3; the 
first almost as large as the radials; the plates of the upper row interlock- 
ing with those irom the tegmen. The anal piece is followed by 2, 3, and 
4 plates. Interdistichals one. Tegmen short, the interambulacral plates 
and orals flat, all of nearly the same size ; the ambulacral pieces the smaller, 
a little convex and formed into ridges. Anal tube of medium size, the plates 
covered with a minute central tubercle. Column moderately large, the nodal 
joints widest, their edges convex, and bordered by small nodes. 
Horizon and Locality.— Upper Burlmgton lmestone ; Burlington and 
Pleasant Grove, Iowa. 
Types in the collection of Wachsmuth and Springer. 
Remarks. — This species differs from A. ¢enuisculptus, with which it has 
its closest affinities, in the mode of ornamentation of the dorsal cup, the 
wider interspaces between the rays at the arm regions, and in having flat 
instead of spiniferous plates in the tegmen. It also occurs at a different 
geological horizon. 
Actinocrinus daphne Hatz. 
Plate LVI. Fig. 1. 
1864. Hari; 17th Rep. N. Y. State Cab. Nat. Hist., p. 52. 
1875. Hatz; Geol. Surv. Ohio, Paleont., Vol. II., Part IL, p. 162, Plate 11, Fig. 11. 
1881. W. and Sp.; Revision Paleoer., Part II., p. 143. 
Calyx of medium size, its exact form indeterminable owing to the crushed 
condition of the specimens; the base truncated only to the width of the 
column; the rays but slightly lobed; the arms given off in clusters as in 
A. tenuisculptus, with moderately wide interspaces between the rays. Plates 
rather delicate ; their surface marked by radiating ridges running from the 
centre of the plates to their margins, where they meet those of adjoining 
plates. The ridges passing up the radials and brachials, and down to the 
basals, somewhat more prominent. 
Basals rather large, forming a spreading cup with a slightly projecting, 
narrow rim around the lower margin, which is readily taken for the upper 
stem joint; interbasal sutures indistinct. Radials longer than wide; the 
costals wider than long; the first hexagonal, smaller than the second, and 
less than two thirds the size of the radials. Distichals smaller than the first 
costals, supporting at one side an arm, at the other two palmars with two 
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