218 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
In the descriptions of the Rhodocrinide, the plate which is interposed 
between the radials is called the first interradial as a matter of convenience, 
and those following it in the dorsal cup interbrachials, although, as elsewhere 
explained, they all belong undoubtedly to the same system of plates. 
RHODOCRINUS Mutter. 
1821. Murtxer (in part); Nat. Hist. of the Crinoidea, p. 106. 
1835. Acassiz; Mem. Soe. Sci. Neuchat., Vol. I., p. 196. 
1841. Méter (in part); Monatsber. d. Berlin. Akad., p. 209. 
1843. Austrx; Ann. and Mag. Nat. Hist-, Vol. X., p. 109. 
1850. D’Orsicny; Prodr. de Paléont., Vol. I., p. 104. 
1853. De Konrncx and Le Hoy (in part); Recher. Crin. Carb. Belg., p. 108. 
1855. Roemer (in part); Leth. Geogn. (Ausg. 3), p. 240. 
1855. (2) Mixver (Wirtgen and Zeiler); Verh. Naturhist. Verein f. Rheinl., Vol. XII., p. 11. 
1857. Procter; Traité de Paléontologie, Vol. IV., p. 314. 
1858. Hatt; Geol. Rep. Iowa, Vol. I., Part Ik, p. 556. 
1861. Hatz; Bost. Journ. Nat. Hist., Vol. VIT., p. 322. 
1868. Merk and Worrnen; Geol. Rep. Illinois, Vol. IIL, p. 476. 
1875. Grenrett; Proceed. Bristol Naturalists’ Soc., Vol. I., Part III., p. 480. 
1879. Zirret; Handb. d. Paleontologie, Vol I., p. 376. 
1881. W. and Sp.; Revision Paleocr., Part II., p. 209 (Proceed. Acad. Nat. Sci. Phila., p. 383). 
1883. WortuEn; Geol. Rep. Illinois, Vol. VII., p. 305. 
1885. Quvensrepr (in part); Handb. d. Petrefactenkunde (Ausg. 3), p. 958. 
1889. W. and Sp.; Geol. Rep. Illinois, Vol. VIII., p. 180. 
1889. S. A. Minter; N. Amer. Geol. and Paleont., p. 277 (not Fig. 417). 
(Not Rhodocrinus Goldf., 1826, Petref. Germanie, Vol. I., p. 212; nor McCoy, 1844, Carbonif. 
Foss. Ireland, p. 180; nor F. Roemer, 1851, Verh. Naturh. Verein f. Rheinl., Vol. VIII, 
p. 358; nor Billings, 1859, Geol. Rep. Canada, Decade 1V.. p. 61; nor Lyon, 1861, Proce. 
Acad. Nat. Sci. Phila., p. 409; nor Hall, 1863, Trans. Albany Inst., Vol. IV., p. 198, and 1876, 
Ist edit. of 28th Rep. N. Y. State Mus. Nat. Hist., p. 189; nor Schultze, 1867, Mon. Echin. 
Hifl. Kalkes, p. 53; nor White, 1880, Proc. United States National Mus., p. 259.) 
Syn. Acanthocrinus ¥. Roemer, 1850. Neues Jahrb. f. Mineralogie, p. 79; Miiller, 1855, Ver 
handl. Naturh. Verein, Vol. XII., p. 8; Hall, 1862 (Subgenus of Rhodocrinus), 15th Rep. 
N. Y. State Cab. Nat. Hist., p. 125. 
Calyx more or less globose, the dorsal cup generally somewhat flattened 
or concave at the base, and constricted in the upper part. Plates flat or 
convex, nodose or spiniferous, their surfaces smooth or striated. Infrabasals 
five, small, sometimes merely occupying the bottom of the columnar con- 
cavity. Basals five, large, all truncated at the upper end. Radials, as a rule, 
larger than the costals, but smaller than the basals. Costals two, not unfre- 
quently coalesced, so as to form practically a single plate. Distichals free in 
part; rarely more than one, and never exceeding three, take part in the 
ealyx. Arms arranged in pairs and bifureating ; biserial, either directly from 
the calyx up, or from the last bifurcation; joints short; the pinnules in 
contact. The first interradial plate is followed by several rows of inter- 
