182 THE CEINOIDEA CAMEEATA OF NOETH AMEEICA. 



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. 



Horizon and Locality. — Hudson Eiver group, Warren Co., Ohio. 



The type specimen now in the collection of Wachsmuth and Springer. 



XENOCRINUS S. A. Miller. 



1881. S. A. Miller; Journ. Cincin. Soc. Nat. Hist., Vol. IV., p. 72. 



1881. W. and Sp.; llevision Palseocr., Part II., p. 184. 



1883. W. and Sp. ; Amer. Journ. Sci., Vol. XXV., p. 266. 



1884. P. H. Carpentee ; Philos. Trans. Eoyal Soc, Part III., p. 930. 



1885. W. and Sp. ; llevision Pala^ocr., Part III., p. 94. 

 1885. W. and Sp. ; Proceed. Acad. Nat. Sci. Pliila., p. 317. 

 1889. S. A. Miller; North Amer. Geol. and Paleeont., p. 287. 



Xenocriniis resembles Reteocrinus, but is without infrabasals. Basals four, 

 forming a low cup, which is decagonal at the upper end ; fi^e 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 

 Pig. 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. 



