G66 THE CRINOIDEA CAMEEATA OF NORTH AMERICA. 



Platycrinus lodensis Hall and Whitf. 

 PMe LXXI. Fig. 6. 



1875. Hall and Whitfield ; Geol. Kep. Oliio, Vol. II., Part II., p. 168, Plate 11, Pig. 3. 

 1881. W. and Sp.; Revision, Part II., p. 72 (Proceed. Acad. Nat. Sci. Phila., p. 246). 



Of medium size. Dorsal cup deeply cup-shaped, the sides almost par- 

 allel ; the plates thin and without ornamentation ; the suture lines not 

 grooved. 



Basals placed almost horizontally, forming a very shallow, saucer-shaped 

 pentangular disk, with a slightly projecting column facet. Eadials rather 

 large, their height equal to the width or slightly exceeding it ; their sides 

 almost parallel, thickened toward the facets, the upper faces a little sloping 

 at the ends, and forming a small notch. Eadial facets deeply excavated to 

 fully two thirds the width of the plates. Costals trigonal, the lower face 

 distinctly convex. Distichals two ; the first resting completely within the 

 facet, once and a half as wide as long ; the second a little wider, and free at 

 the outer side, but suturally connected with its fellow of the same ray ; the 

 upper angle obtuse, supporting two arms, making four to the ray. Arms 

 proportionally long and heavy throughout their full length, rounded on the 

 back and sides. They are composed from the second or third plate up of a 

 double series of short, transverse pieces. Structure of ventral disk unknown. 

 Columnar joints very slightly elliptic. 



Horizon and Locality. — Cuyahoga shales, Waverly group, at Lodi, Medina 

 Co., and at Royalton, Ohio. 



Type at Columbia College, New York. 



Remarks. — The form and size of the distichals are not correctly repre- 

 sented in Hall and Whitfield's figure, and were changed in our figure from a 

 specimen in our collection. 



