FOSSILS OF THE KEOKFK GROUP. 489 



CYATHOCRLSTTES? POTERIUM, M. and \V. 



PI. 12, Fig. 4. 

 Cyathocrinite* ? poterium, MEEK and WORTHEX, 1870. Proceed. Aoad. Xat. Sci., Phila., p. 24. 



BODY small, depressed, subglobose, somewhat flattened 

 below and contracted above. Basal plates of moderate 

 size, pentagonal in form, and spread out horizontally so as 

 form a nearly flat pentagonal disc, excepting that the salient 

 angles are curved upward a little ; facet for the attachment 

 of the column small, compared with the size of the base, 

 round, and not impressed. Subradial plates large, forming 

 the widest part of the body, convex on the outside, but not 

 from thickening; about as wide as long, hexagonal, with 

 perhaps the exception of one on the anal side, of heptagonal 

 form; all curving under below to connect with the base. 

 First radials somewhat smaller than the subradials, wider 

 than long, pentagonal in form, and provided above with 

 very small, shallow sinuses for the reception of the second, 

 wjiich are small, but more than filling the shallow sinuses. 

 Third radials, in two of the arms seen, small, and bearing 

 on each of their superior sloping sides a long, very slender, 

 subcarinated arm, which bifurcates on the second piece 

 above, while the divergent divisions subdivide two or three 

 times again above, at intervals of three or four pieces; the 

 divisions and subdivisions all being very slender, and com- 

 posed of joints about twice as long as wide. In two of the 

 rays seen, however, the free arms are simple from their 

 origin on the first radials at least as far up as to the sixth 

 piece, inclusive, (which is as far as they can be traced in 

 the specimen,) and present the remarkable character of 

 having the second, third and fourth pieces greatly dilated, 

 or alate on each side, so as to be nearly two-thirds as 

 broad as the whole body below, though the first piece next 

 the body (second radial) is narrow, and nearly twice as 

 long as wide, as are the fifth and sixth pieces. Surface 



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