RHODOCRINID.E. 233 
Infrabasals placed at the bottom of a concavity; forming a penta- 
gon, of which small portions are exposed beyond the column. — Basals 
smaller than the radials and without nodes or tubercles; they rest within 
the lower concavity, except their extreme upper ends, which bend slightly 
upwards. Radials large, forming a rim upon which the calyx rests; their 
tubercles quite long, rounded at the ends, and directed obliquely downward. 
Costals comparatively large, their tubercles connected with one another, and 
sometimes with those of adjoining radials and interradials by obscure ridges. 
Distichals one in the calyx, provided with a horse-shoe-shaped facet for the 
reception of the free brachials. Arm openings elongate, facing laterally ; 
structure of the arms unknown. — First interradial followed by interbrachials 
in succession of 2, 2, and two more between the arm openings. The anal 
interradius has three plates in the second and succeeding rows, but the plates 
are not formed into a ridge or placed in a straight line, their arrangement 
being rather irregular. Interdistichals one, on a level with the arm openings. 
Tegmen very small, flat, and of the plates only the ends of the tubercles vis- 
ible from a side view ; the plates large and irregularly arranged. Anal open- 
ing marginal. 
Horizon and Locality. — Age of the Lower Burlington limestone, Lake 
Valley, New Mexico. 
Types in the collection of Wachsmuth and Springer. 
Remarks. — This species, which has the general habitus of certain forms 
of Gilbertsocrinus, differs from all other species of Rhodocrinus in the form of 
its nodes, which cover almost the whole face of the plates. The largest 
nodes occur on the radials, and not on the basals, those of the latter plates 
being often wanting altogether. It also differs in the form and greater size 
of the costals and distichals. 
GILBERTSOCRINUS Putttires. 
1836. Puriuirs; Geology of Yorkshire, Part II., p. 207. 
1841. Mixrer; Berlin. Acad. der. Wissensch., p. 209. 
1849. D’Oreieny; Prodréme I., p. 155. 
1852. D’Orsieny; Cours élément., Vol. IL, p. 142. 
1865. Merk and Wortuen; Proceed. Acad, Nat. Sci. Phila., p. 166. 
1872. Hatx; N. Y. State Mus. of Nat. Hist., Bull. I., Plate 1a and Plate VI. 
1873. Merxand Wortuen; Geol. Rep. Illinois, Vol. V., p. 389. 
1875. GrenreLt; Proceed. of Bristol Naturalists’ Soc., Vol. I., Part III., p. 483. 
Syn. Ollacrinus CUMBERLAND ; 1826, Appendix to Reliquiw Conservate, Plate D ; 1877, Wachsmuth ; 
Amer. Journ. Sci., Vol. XIV., p. 125 ; 1878, Zittel; Handb. d. Palaeont., Vol. I., p. 876 ; 1881, 
W. and Sp.; Revision Paleocr., Part IL., p. 213; and Proceed. Acad. Nat. Sci. Phila., p. 387; 
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