310 PROCEEDINGS OF THE ACADEMY OF 



divided, it will be readily distinguished by its very differently 

 formed body, its more slender and more frequently divided as 

 well as longer arms, and its more slender column. 



Locality and position. — Cincinnati group, 100 feet below tops 

 of hills, at Cincinnati, Ohio. Mr. Dyer's collection. 



HETEEOCRINUS SUBCRASSUS, M. k W. 



Heterocrinns saber assus, Meek & Wortheu, 1865. Proceed. Acad. Nat. 



Sci. Pliilad., p. 145; Illinois Report, vol. III., p. 325, pi. 4, fig. 5, a, 



b, c, d. 



Heterocrinus (locrinus) polyxo, Hall, 1866?. Descriptions of some new 



species of Crinoidea and other fossils, from the Silurian Strata, etc., 



p. 5 ; dated, Nov. 1866. 



A careful comparison shows the proposed species H. pohjxo^ 

 Hall, 1866?, to be in all respects identical with H. subcrassus, M. 

 & W., 1865. Prof. Hall places it under a subgenus locrinus, and, 

 if there be sufficient grounds for so doing, the name of the spe- 

 cies, when written in full, would be Heterocrinus {locrinus) 

 subcrassus. 



POTERIOCRINITES (DENDEOCRINUS) DYERI, Meek. 



Body small, obconic, or tapering regularly to the column from 

 above. Basal pieces longer than wide, the greatest breadth being 

 across between the superior lateral angles ; all pentagonal. Sub- 

 radial pieces a little longer than the basals, longer than wide, andr 

 excepting the one on the anal side (which is largest and hepta- 

 gonal), all hexagonal. First radials of about the size of the sub- 

 radials, but proportionally broader, being a little widei- than long, 

 with a general pentagonal outline, though all, excepting the one 

 on the right of the anal series, have the superior lateral angles a 

 little truncated ; while the second piece in that ray, which, as is 

 usual in the group, corresponds to the first in the other rays, also 

 has these angles truncated. Succeeding radials in all the ra_ys 

 much narrower, about as long as wide, or slightly longer, and 

 numbering from five to six or seven pieces below the first bifurca- 

 tion. Arms remarkably long and slender, laterally compressed, 

 more or less angular on the dorsal side, and giving ofl[', alternately 

 on opposite sides, at distant intervals above the first bifurcation 

 of each ra}^, from three to four or more scarcely diverging divi- 

 sions that are slightly more slender than the arms, from which 



[February 13, 



