182 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
constructed of extremely short, slightly convex, cuneate pieces. Pinnules 
composed of five or more joints; long, slender, and not in lateral contact. 
The first pinnule is borne upon the second distichal, above which every 
joint, the axillaries excepted, is pinnule-bearing. Interradial areas more 
substantial than in the preceding species, the plates stouter, and the median 
portions rather convex than concave. Each area contains from twenty-five 
to thirty pieces, some larger than others, of all possible shapes, and indis- 
criminately arranged. The construction of the anal side is not known. The 
interdistichal areas apparently extend to the top of the fifth distichals, are 
comparatively flat, and composed of similar pieces to those of the interradial 
spaces. Construction of disk and anus unknown. Column near the calyx 
distinctly pentangular; the nodal joints longer, slightly projecting and 
rounded at the margin; the internodal ones shorter, and provided with 
sharp edges. 
Florvizon and Locality. — Hudson River group, Warren Co., Ohio. 
The ¢ype specimen now in the collection of Wachsmuth and Springer. 
XENOCRINUS 5S. A. Miter. 
1881. §S. A. Mitrer; Journ. Cincin. Soc. Nat. Hist., Vol. IV., p. 72. 
188]. W. and Sr.; Revision Paleocr., Part II., p. 184. 
1883. W.and Sp.; Amer. Journ. Sci., Vol. XXV., p. 266. 
1884. P.H. Carpenter; Philos. Trans. Royal Soe., Part IIT., p. 930. 
1885. W. and Sp.; Revision Palwocr., Part IIT., p. 94. 
1885. W. and Sp.; Proceed. Acad. Nat. Sci. Phila., p. 317. 
1889. S. A. Mitrer; North Amer. Geol. and Paleont., p. 287. 
Xenocrinus resembles Reteocrinus, but is without infrabasals. Basals four, 
forming a low cup, which is decagonal at the upper end; five of its sides 
supporting the five radials, the five others the interradial and anal plates. 
This arrangement gives to the basals, owing to their abnormal number, a 
very irregular form, no two of the plates being alike. 
Radials generally a little larger than the costals.  Costals 
two, the sides bending abruptly inward and forming highly 
elevated ridges; the distichals to about the fifth or eighth 
plate form part of the calyx. The lower of these plates 
are larger, and more or less resemble the costals, while the 
Fic. 7. upper ones are more like free arm plates. Arms ten, 
simple, rather stout; composed of very short cuneiform 
pieces, which at the tips of the arms slightly interlock. 
