Paleontology of the Cincinnati Group. 113 



and the third pentagonal, and supporting on its superior 

 sloping sides the first divisions of the rows ; secondary radials 

 8 to 11 in number, rapidly diminishing in length upward to 

 the second bifurcation or commencement of the arms just 

 below where a few of the smaller pieces seem to be free and 

 bear pinnules on their inner sides ; further down the second 

 and fourth secondary radials of each ray give off, alternately 

 on each side, small divisions that do not become free, giving 

 rise to pinnules at the summit of the body ; anal area a little 

 wider than the interradial areas ; first anal plate of about 

 the same size as the first radials, hexagonal, and supporting 

 in the next range 3 pieces arranged with the middle one higher 

 than the others ; while above these 3 smaller pieces can be 

 seen arranged in the same way in the third range and 3 to 4 

 or 5 in the fourth ; the middle plates of this series form a 

 direct vertical row that has a rather prominent mesial, rounded 

 ridge extending all the way up from the middle of the lowest 

 pieces of about the same size as those passing up the primary 

 and secondary radial series, while the other plates on each 

 side and other parts of the lowest pieces are ornamented with 

 radiating costae of smaller size, like those of the interradial 

 pieces ; interradial areas, not excavated below, but becoming 

 moderately concave above ; first interradial pieces about the 

 size of the second primary radials, hexagonal, and supporting 

 2 other smaller pieces in the next range, that bear between 

 their superior sloping sides a fourth smaller piece ; while 

 above this there are two pieces in the next range that con- 

 nect with the pieces of the little lateral division of the sec- 

 ondary radials, and perhaps some other small intercalated 

 pieces, filling the upper part of the interradial areas ; axilliary 

 areas flat, and each occupied by an hexagonal or heptagon al 

 piece about the size of the second piece of each secondary 

 radial, while the space above is occupied by several much 

 smaller pieces ; arms 20, 4 to each ray, rounded on the dorsal 

 side, slender, of moderate length, very gradually tapering, 

 simple, and composed of very short, slightly wedge -form 

 pieces, each of which bears a pinnule at its inner lateral end ; 

 pinnules slender, rather closely arranged, deeply furrowed on 

 the inner side and apparently composed of rather long joints ; 

 surface of the body plates all ornamented with distinct radi- 



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