RETEOCRINID &. 183 
Interradial spaces deeply impressed; composed of numerous minute 
pieces without definite arrangement; they rest upon the basals, separating 
the rays from their bases up. Anal interradius wider than the four others; 
divided longitudinally by a row of folded plates, which like the radials have 
a prominent ridge upon the outer surface, and a groove at the inner floor. 
The ridge ends in a small protuberance containing the anal opening, which 
points upwards. Interdistichal spaces also deeply depressed, and filled by 
irregular, minute plates, which like those between the main rays pass imper- 
ceptibly into the disk. Ventral disk comparatively flat, composed through- 
out of very small pieces; orals being unrepresented, and the disk ambulacra 
subtegminal. 
Column quadrangular, with pentangular central canal, the angles of 
which are directed interradially. 
Distribution. — This genus, so far as known, is limited to the upper part 
of the Hudson River group of Ohio. 
Type. — Xenocrinus pencillus Miller. 
Remarks. — We place in this genus Glyptocrinus Bueri Meek, which, as we 
have discovered, has a quadrangular stem and four basals. Xenoerinus is the 
only monocyclic genus in which interradials come in contact with the basals 
at all sides, but we doubt if its interradials separated the rays as completely 
as in the case of the Rhodocrinide. In a specimen of X. Laer from the 
collection of Mr. I. H. Harris (Plate IX. Fig. 5c), in which portions of the 
inner floor are exposed, it is plainly seen that the lower ends of adjoining 
radials touch each other, and after a careful study of the structure we are 
inclined to believe that the small accessory pieces, which seem to separate 
the radials, rest upon the lower outer margins of the plates, and not between 
the plates. 
Xenocrinus penicillus Mitrer. 
Plate LX. Figs. Ga, b. 
1881. S.A. Minter; Journ. Cincin. Soc. Nat. Hist., Vol. IV., p. 72, Plate 1, Fig. 3; and ibid., p. 176, 
Plate 4, Fig. 6. 
1883. W. and Sp.; Amer. Journ. of Sci., Vol. XXV., p. 266, and 1885, Revision Paleocr. Part IL, 
p- 96. 
A small species. Calyx elongate, once and a half as high as wide, ob- 
conical at the lower end, then rising almost vertically to the free arms; the 
radials and brachials highly elevated, folded lengthwise with rounded back ; 
the interradial spaces deeply impressed, the plates somewhat nodose. 
