344 PROCEEDINGS OF THE ACADEMY OF [1879. 



1843. Poteriocr. pentagonus Austin. (Cladocr. pentagonus.) Ann. & Mag. Nat. 



Hist., vol. ii. p. 198 ; Rec. and Foss. Crin., p. 86, pi. 11. figs. 2 a-f. Sub- 



carb. England. 

 1858. Poteriocr. rugosus Shumard. Trans. St. Louis Acad. Sci. Coal Measures. 



(No means of comparison. ) 

 1869. Poteriocr. simplex Lyon. (Not Pot. (Scaphiocr.) simplex Hall =Graphiocr. 



simplex.) Trans. Am. Philos. Soc. Phil., p. 458, pi. 26, fig. f. Upper 



Helderberg, Devonian. Falls of the Ohio. 

 1821. Poteriocr. tenuis Miller. Hist. Crin., p. 71; Sehlotheim, 1822; Nachtr. 



Petrefactenk., vol. ii. pi. 25, fig. 2; Austin, 1843, Rec. and Foss. Crin., p. 



83, pi. 10, figs. 5 a, b. Mountain limest. Subcarb. England and Ireland. 

 *1861. Poteriocr. Wortheni Lyon. (Cyathor. Wortheni.) Proc. Acad. Nat. Sci. 



Phil., p. 410. Encrinal limest. Devon. Jefferson Co., Ky. 



15. GRAPHIOCRINUS De Koninck & Lehon. 



1853. Graphiocrinus De Kon. & Leh. Crin. Carb. Belg., p. 115. 



1858. Scaphiocrinus (in part) Hall. Geol. Rep. Iowa, vol. i. pt. 2, p. 549. 



1879. Phialocrinus(?) Trautschold. Kalkbrucke Mjatch., p. 122. 



A. Typical form. 



In general aspect Graphiocrinus closeh' agrees with a form of 

 Poteriocrinus for which we have proposed the name Scytalocrinus, 

 from which, however, it differs clearly in the anal area, which in 

 Graphiocrinus has but a single plate, while in the other it has 

 three. De Koninck, in his generic description, mentions only two 

 orders of plates as constituting the calyx, in which he is evidently 

 mistaken. We have before us several species from the Burlington 

 limestone, which have heretofore been referred by their authors to 

 Scaphiocrinus, but which agree in the clearest manner with the 

 typical Graphiocrinus encrinoides. They all, like the typical spe- 

 cies, have ten arms except an undescribed species, which we 

 think belongs to this type, and which has only five constructed 

 of simple joints with parallel sutures; they have one large bra- 

 chial and a single anal plate, extending beyond the general limit 

 of the calyx; and whenever the column is attached there is no 

 trace of underbasals, yet these plates are found in every one of 

 those species when seen with the column removed. We can no 

 longer doubt, from the evidence of our specimens, that the under- 

 basals, as suggested by Hall and Meek & Worthen, are also 

 present in the Belgian species, but hidden from view by the 

 column, and that all the above-mentioned species belong to the 

 same genus. We therefore propose a revision of the generic 

 formula, protesting, however, against the assertion of the authors 



