1879.] NATURAL SCIENCES OF PHILADELPHIA. 327 



1858. Barycr. tumidus Hall. (Cyathocr. tumidus.) Geol. Rep. Iowa, vol. i. 



pt. ii. p. 624, pi. 18, figs. 1 b, c. B. tumidus, 1868. Proc. Acad. Nat. 



Sci. Phil., p. 340. Keokuk lhnest. Subcarb. Keokuk, Iowa. 

 1861. Barycr. Wachsmuthi Meek & Worthen. (Cyathocr. Wachsmuthi.) Proc. 



Acad. Nat. Sci. Phil., p. 136, Geol. Rep. 111., vol. iii. p 482, pi. 16, fig 5 ; 



B. Wachsmuthi, 1868. Proc. Acad. Phil., p. 340. Lower Burl, limest. 



Subcarb. Burlington, Iowa. 



14. POTERIOCRINUS, Miller. 



1821. Poteriocrinites Miller. A History of the Crinoidea, p. 65. 



1835. Poteriocrinus Agassiz. Mem. de la Soc. de Neuch., vol. i. 



1836. Poteriocrinus Phillips. Geology of Yorkshire, p. 205. 

 1843. Poteriocrinus Austin. Rec. and Foss. Crin., p. 68. 



1853. Poteriocrinus de Koninck & Lehon. Recher. s. 1. Crin. Belg., p. 84. 

 1849. Cupressocrinus McCoy. Ann. & Mag. Nat, Hist., ser. ii. vol. ii. (not 



Goldf.). 

 1858. Scaphiocrinus Hall. (Subgenus of Poteriocr.) Geol. Rep. Iowa, p. 



550. (Not Oraphiocrinus de Koninck & Lehon.) 

 1866. Poteriocrinites Meek & Worthen. Geol. Rep. Ill, vol. ii. p. 179. 

 1866. Scaphiocrinus Meek & "Worthen. (Subgenus of Poteriocr.) Ibid. 



vol. ii. p. 237. 



1866. Poteriocrinus Schultze. Mon. Echinod. Eifl. Kalk. p. 42. 



1867. Hydriocrinus Trautschold. Bull, de la Soc. Imp. des Naturalists de 



Moscou, p. 16. 



(Diagram PI. 2, No. 7.) 



In no other genus of the Crinoids is there found so much con- 

 fusion as in the one now under consideration. This is partly due 

 to* the imperfect preservation of the specimens from which the 

 earlier descriptions were made, and also, no doubt, to the species 

 themselves upon which Miller founded the genus. Neither of his 

 two species of Poteriocrinus can be considered characteristic types 

 of the genus, and unfortunately among his four species of Cya- 

 thocrinus the genus with which Poteriocrinus was afterwards 

 so often confounded only one can be properly claimed for that 

 genus, two of them having been later referred to very distinct 

 groups, and the fourth is a Poteriocrinus. 



According to Miller, the pelvis of Poteriocrinus is composed 

 of five pentagonal plate-like joints, supporting five hexagonal in- 

 tercostal plate-like joints, and five plate-like scapulas with an 

 intercostal and an interscapulary plate interposed ; an arm pro- 

 ceeds from each scapula; column round, composed of narrow 

 joints with a central perforation. This embraces everything in 

 Miller's description which might be deemed of generic importance, 



