358 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
the lower side of the spine there is but one ridge, which leads to the basals. 
The ridges upon the first interbrachials culminate in a sharp node in the 
centre. 
Basals comparatively small, occupying but half the depth of the con- 
cavity. Radials very large, the lower half curving abruptly inward, and 
forming a sharp edge upon which the cup rests. Costals very small, the 
two together less than half the size of the radials; the first from two to 
three times as wide as long; the second a very little higher and truncated at 
the top. Distichals, palmars, and interdistichals very small; the first inter- 
brachial unusually large, and as wide as long. Ventral disk stout, and to 
the base of the tube twice as high as the dorsal cup; the sides rising verti- 
cally to the top of the trigonal plate of the first ring, whence they slope 
slightly to the summit of the ten larger ones, and more rapidly to the tube, 
which near its base is moderately thick. The ten larger plates of the first 
ring are longer than the whole dorsal cup, the intervening trigonal ones but 
half as long. The former, as seen from gutta percha impressions, have long 
spiniform appendages, which probably resembled those of Cadlicrinus murchi- 
sonianus Angelin (Iconogr. Plate 28, Fig. 14); they are a little compressed 
at the sides, and are directed upwards and outwards. ‘The trigonal pieces 
also rise into spiniform partitions, but these are shorter and smaller gener- 
ally. Structure of the arms unknown. 
Horizon and Locality. — Niagara group; Racine, Wisce., and Chicago, IIls. 
Types in the N. Y. State Cabinet of Natural History at Albany. 
Remarks. — The large collections of Mr. Thomas A. Greene of Milwaukee, 
and Mr. W. C. Egan of Chicago, contain a few specimens in which the dor- 
sal cup is unusually expanded at the arm bases, less broadly truncated at 
the bottom, and the first costals somewhat larger; while otherwise agreeing 
with the rest of the specimens. These specimens do not agree with C. cor- 
nutus, var. excavatus Hall, which was not accepted by Whitfield, and we think 
that both these forms may be regarded as variations of C. cornutus. 
(?) Callicrinus ramifer F. Rormer. 
1860. Eucalyptocrinus ramifer — Roemer Silur. Fauna West. Tenn., p. 51, Plate 4, Figs. 4a, 0, e 
1885. Eucalyptocrinus ramifer —W. and Se.; Revision Paleocr., Part III., p. 134. 
This species is only known from the general form of its dorsal cup, and 
there is some doubt whether it should be referred to Callicrinus or to a new 
venus. It differs from the other species of that genus in the size of its bas- 
