252 PROCEEDINGS OF THE ACADEMY OP [1881. 



and wliieh give off long pinnules, composed of a large number of 

 short joints. 



Column cylindrical. 



Until other specimens are discovered, we must consider Cotyle- 

 donocrinus an abnormal form of Dichocrinus. 



Casseday and Lyons' only species is : — 



1860. Cotyledonocrinus pentalobus. Proc. Amer. Acad. Arts, and Sci., vol. v, p. 26. 

 Warsaw limest. Grayson Co., Kentucky. 



h. Hexackinites. 



7. HEXACRINUS Austin. 



1843, Austin. Mon. Rec. and Foss. Crin., p. 48. 



1853. De Kon. and Leh. Rech. Crin. Carb. Belg., p. 160. 



1855. F. Roemer. Letbaea Geogn. (Ausg. 3, Per. 1), p. 244. 



1857. Job. Miiller. Neue Ecbin. Eifl. Kalk, p. 85. 



1857. Pictet. Traite de Paleont., iv, p. 831. 



1867. Scbultze. Mon. Ecbinod. Eifl. Kalk, p. 71. 



1879. Zittel. Handb. der Palajontologie, p. 365. 



Syn. Platycr. Phil., 1841 (not 1836). Pal. Foss. Cornw., p. 28. 



Syn. Platycr. Goldf. (in part), 1838. Nova Acta. Ac. Leop., xix, 

 p. 343. 



Syn. Platycr. Agas. (in part), 1835. Mem. Soc. Neucb., i, p. 197. 



Syn. Platycr. Aust. (in part), 1842. Ann. and Mag. Nat. Hist., x, 

 p. 109. 



Syn. Platycr. F. A. Roemer, 1843. Verstein. d. Harzes. 



Syn. Platycr. F. Roemer, 1851. Vei-h. naturb. Verein Rbeinl., p. 

 362. 



Syn. Platycr. D'Orbigny (in part), 1850. Prodr. Pal., i, p. 103. 



Syn. Platycr. Lyon, 1860. Trans. Am Pbilos. Soc, p. 459. 



Generic Diagnosis. — Body obconical, pear-shaped orsubglobose ; 

 surface generally elaborately sculptured or nodose; symmetry 

 decided 1^^ bilateral. 



Basal disk large, in form of a shallow cup ; hexagonal ; composed 

 of three equal plates. Five of its sides support a first radial 

 each, the sixth a large anal plate, which extends to the full height 

 of the first radials. Primary radials 2 X 5, the first very large, 

 apparentlj' quadrangular but actuall}'^ hexagonal; increasing in 

 width from the base up; upper margin excavated. Second radials 

 minute, triangular, rarely filling the whole excavation, which 

 generally encloses a part of the first secondary radials, the latter 

 forming the base of two free appendages to each ray. The free 



