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762 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
Radials a little longer than wide; the lower faces moderately convex; the 
lateral ones parallel; the upper nearly straight, not sloped at the outer ends, 
and but little impressed at the facet, which is narrow and somewhat thick- 
ened around the margin. Anal plate generally wider at the lower end than 
the radials, and one fourth narrower at the top; its lower face obtusely 
angular. All parts above the radials unknown. Column round and small. 
Horizon and Locality. — Lower Burlington limestone, Burlington, Iowa. 
Lype in the Museum of Comparative Zodlogy. 
oo 
—— 
Dichocrinus ornatus W. and Sp. 
Plate LX X VIL. Fig. 6. 
1881. Dichocrinus ornatus —W. and Sp.; Revision Palocr., Part IT., p. 84. é 
Syn. Dichocrinus sculptus —Cassepay and Lyon (not De Koninck and Le Hon, 1853); Proceed. 
Amer. Acad. Arts and Sci., Vol. V., p. 25. 
A very small species. Calyx to the top of the radials about as wide as 
high; regularly cup-shaped ; broadly truncated at the lower end; the sides 
a little convex; the upper margin slightly contracting. Plates covered 
by conspicuous, irregular, undulating ridges, two of which descend from the 
top of the dorsal cup to the foot of the basals, two others obliquely in the 
direction of the lower lateral angles of the radials, touching slightly the 
upper end of the basals, and two shorter ones pass out to the lateral faces of 
the radials. 
Basal cup saucer-shaped, occupying two fifths the height of the calyx; 
the truncated lower face surrounded by a well defined undulating rim. 
Radials a little longer than wide, widest at the top; facets small and pro- 
jecting outward. Anal plate almost as large as the radials, narrowest above. 
Costals two, short; occupying less than one half the width of the radials. 
Distichals two or three. Arms four to the ray, slender; composed of long 
cuneate joints which gradually interlock without being truly biserial, Pin- 
nules long. The arms in most of the specimens are spread out horizontally. 
Ventral disk low-convex ; anus directed laterally. Column round; the nodal 
joints projecting and provided with one or two long cirri. 
Horizon and Locality.—St. Louis group; the type specimen in the 
collection of Major 8. S. Lyon came from Hardin County, Ky., that figured © 
by us from near Mt, Pleasant, Iowa. 
Remarks. — This is the smallest known species of Dichocrinus, and is 
readily recognized by the spreading arms, long pinnules, and the striz 
along the calyx plates. 
