350 THE CKINOIDEA CAMERATA OF NORTH AMERICA. 



Tupes in the collection of W. C. Egan, Esq., of Chicago. 



Remarks. — This species difiers from all preceding ones in the depressed 

 form of the dorsal cup, the width and depth of the basal concavity, and the 

 position of the radials which are almost at right angles to the plates of the 

 upper end. It was originally desci'ibed from natural casts, but Mr. Egan 

 has since obtained from the same locality a specimen with the plates intact, 

 from which our description is made. 



Doubtful species described from natural casts.* 



EucalyptOCrinUS splendidus (Xioost) Hall and Whitfield. 



1848. Troost ; List Cria. Tenu., Proceed. Amer. Assoc. Adv. Sci., p. 60 (without description). 

 1875. Hall and 'Whiifield ; Geol. Surv. of Ohio, Palseout., Vol. II., p. 128, Plate 6, Fig. 12. 



Closely allied to the preceding species, and perhaps identical with it. 

 As in that species, the general form is subcylindrical, flattened at both ends, 

 the arms are twice as long as the dorsal cup, and the I'adials are not seen in 

 a side view, or only their extreme upper ends ; the disk, however, to judge 

 from the cast, is proportionally shorter, and the first costals are higher. The 

 basal concavity cannot be seen in the specimen, but must have included the 

 preater part, if not the whole, of the radials. First costals quadrangular, 

 nearly as long as wide ; the apex of the second slightly truncated by the 

 interdistichal ; the distichals considerably smaller than the costals ; the first 

 interbrachial large, a little longer than wide. The proportions of the other 

 plates indeterminable. Disk hemispherical, the tubular canal in the cast as 

 long as the rest of the calyx, and funnel-shaped at the upper end. 



Horizon and Locality. — Niagara group; Springfield, 0. 



Type in the collection of Professor Orton. 



Eucalyptocrinus rotundus S. A. Millek. 



1882. S. A. Miller ; Journ. Cineiu. See. Nat. Hist., Vol. V., p. 82, Plate 3, Figs. 4 and 4 a, h, c. 



Of small size. Crown globose. The inner cavity of the calyx, as seen 

 in the cast, much wider than high, the canal within the neck wide and of 

 nearly uniform width. Dorsal cup low-saucer shaped ; the basal concavity 

 small, and apparently filled completely by the upper joints of the column. 

 Radials wider than long, the upper face concave. First costals twice as wide 



* We are willing to admit that most of these forms differ specifically from one another, but we are 

 unable to see how the casts can bo satisfactorily compared with species described from the test, especially in 

 a genus like Eucalyptocrinus in which the difi'ercntiations are but very slight. 



