218 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



In the descriptions of the Rhodocrinidse, 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 Miller. 



1821. Miller (in part) ; Nat. Hist, of the Crinoidea, p. 106. 



1835. Agassiz; Mem. Soc. Sci. Neuchat., Vol. I., p. 196. 



1841. MuLLER (in part); Monatsber. d. Berlin. Akad., p. 209. 



1843. Austin; Ann. and Mag. Nat. Hist., Vol. X., p. 109. 



1850. D'Orbigny; Prodr. de Paleont., Vol. I., p. 104. 



1853. De Koninck and Le Hon (in part); Recher. Crin. Carb. Belg., p. 103. 



1855. RoEMER (in part); Letli. Geogn. (Ausg. 3), p. 240. 



1855. (?) MtJLLER (Wirtgen and Zeiler) ; Verli. Naturliist. Verein f. RheiiiL, Vol. XII., p. 11. 



1857. Pictet; Traite de Paleontologie, Vol. IV., p. 314. 



1858. Hall; Geol. Rep. Iowa, Vol. L, Part II., p. 556. 

 1861. Hall ; Post. Journ. Nat. Hist., Vol. VII., p. 322. 



1868. Meek and Worthen; Geol. Rep. Illinois, A^ol. III., p. 476. 



1875. Greneell ; Proceed. Bristol Naturalists' Soc., Vol. I., Part III., p. 480. 



1879. Zittel; Handb. d. Palseontologie, Vol I., p. 376. 



1881. W. and Sp. ; Revision Palgeocr., Part II., p. 209 (Proceed. Acad. Nat. Sci. Phila., p. 383). 



1883. Worthen; Geol. Rep. Illinois, Vol. VII., p. 305. 



1885. QuENSTEDT (in part) ; Handb. d. Petrefactenkunde (Ausg. 3), p. 958. 



1889. W. and Sp.; Geol. Rep. Illinois, Vol. VIII., p. 180. 



1889. S. A. Miller; N. Amer. Geol. and Paleont., p. 277 (not Fig. 417). ^ 



(Not modocrinus Goldf., 1826, Petref. Germanise, Vol. L, p. 212 ; nor McCoy, 1844, Carbonif. ' 



Poss. Ireland, p. 180; nor P. Roemer, 1851, Verli. Naturh. Verein f. Rlieinl, Vol. VIII., 



p. 358; nor Billings, 1859, Geol. Rep. Canada, Decade IV., p. 61; nor Lyon, 1861. Proc. 



Acad. Nat. Sci. Phila., p. 409 ; nor Hall, 1863, Trans. Albany Inst., Vol. IV., p. 198, and 1876, 



1st edit, of 28tli Rep. N. Y. State Mus. Nat. Hist., p. 139 ; nor Schultze, 1867, Mon. Echin. 



Eifl. Kalkes, p. 53; nor White, 1880, Proc. United States National Mus., p. 259.) 

 Syn. Acanthocrinus P. Roemer, 1850. Neues Jalirb. f. Mineralogie, p. 79; Miiller, 1855, Ver 



handl. Natnrh, 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. Eadials, 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 

 calyx. Arms arranged in pairs and bifurcating ; 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- 



