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766 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
Dichocrinus delicatus W. and Sp. (nov. spec.). 
Plate LX XVIT, Fig. 13. 
Of the type of D. devis, but smaller; the calyx more elongate, its height 
twice its width; cross section circular; plates thin and apparently without 
ornamentation ; suture lines indistinct. 
- Basals occupying two fifths the height of the dorsal cup, the sides a little 
convex. Radials fully twice as long as wide; the lateral faces about parallel; 
the upper face nearly straight, not sloping at the sides; the facet for the 
reception of the brachials slightly indented, occupying less than one half the 
width of the plates. Primary brachials two, short, of equal width; the sec- 
ond a little longer, its upper sides forming an obtuse angle, and giving off 
two arms which remain simple throughout. Arms long, cylindrical, but little 
tapering; uniserial, composed of very short quadrangular joints; their upper 
and lower faces almost parallel; the pinnules in rather close contact, long, 
slender, Anal plate of equal length with the radials, the upper end narrower 
than the lower. Ventral disk and anal opening not visible in the specimens. 
Horizon and Locality. — Kinderhook group of Marshall Co., Iowa, and 
Lower Burlington limestone of Burlington. 
Types in the collection of Wachsmuth and Springer. 
Ltemarks. — Dichocrinus delicatus made its appearance before D. Jevis, and 
may be regarded in a phylogenetic sense as the earlier stage of that species, 
as indicated by the arm structure; the arm joints are quadrangular in the 
several specimens found, while in that species they are cuneate and inter- 
locking at the tips of the arms. Besides, this has invariably two arms to the 
ray instead of four as in D. levis, and the specimens are generally smaller. 
Dichocrinus superstes W. and Sp. (nov. spec.). 
Plate LXXVI. Fig. 12. 
A small species of the type of D. delicatus. Dorsal cup obconical, higher 
than wide, spreading more rapidly at the basal cup than from there upwards. 
Cross section hexangular, owing to an angularity passing from the radial 
facets and upper part of the anal plate to the lower ends of the basals. 
Plates without ornamentation, thick, and the sutures obscure, except the 
interradial, which are somewhat grooved at the upper end. 
” 
