BATOCRINID.A. 385 
medium size, extending beyond the tips of the arms. Structure of column 
unknown. 
Horizon and Locality.—- Upper Burlington limestone ; Burlington, Iowa. 
Batocrinus laura, var. sinuosus (Hatt). 
1860. Actinocrinus sinuosus— Hat; Suppl. Geol. Rep. Iowa, p. 27. Photogr. plate (1872) 3 4, Figs. 
8 and 9. 
1873. Batocrinus sinuosus — Murx and WortHen; Geol. Rep. Illinois, Vol. V., p: 368. 
1881. Batocrinus sinuosus — W.aund Sv.; Revision Paleocr.,. Part IL., p. 168. 
This form is so closely allied to Batocrinus laura that we regard it 
a variety of that species. It is said to differ in having a more pointed base, 
a deeper groove between the two posterior rays, and that the interbrachials 
of the anal side pass into the interambulacral plates, thereby approaching 
Lobocrinus. The anal tube is moderately large and almost central. 
Horizon and Locality. — Same as last. 
Type in the Mlinois State collection at Springfield. 
ERETMOCRINUS Lyon and Cass. 
1859. Lyon and Cassepay; Amer. Journ. Sci. and Arts, Vol. XXVIII. (ser. 2), p. 241. 
1866. SHuMmarp (subgenus of Actinocrinus) ; Catalogue Paleoz. Foss. Part I., p. 369. 
1869. Murx and Wortuen (subgenus of Batocrinus); Proceed. Acad. Nat. Sci. Phila., p. 350. 
1873. Merk and WortHen (subgenus of Batocrinus); Geol. Rep. Illinois, Vol. V., p. 368. 
1878. W.and Sp.; Proceed. Acad. Nat. Sci. Phila., p. 235. 
1879. Zrrren (subgenus of Actinocrinus) ; Handb. der Paleontologie, Vol. I., p. 370. 
1881. W. and Sr.; Revision Paloer., Part II., p. 170 (Proc. Acad. Nat. Sci. Phila., p. 344). 
1885. W. and Sp.; Revision Paleoer., Part I1I., p. 113 (Proc. Acad. Nat. Sci. Phila., p. 335). 
1890. S. A. Mizzzr; North Amer. Geology and Paleont., p. 242. 
Syn. Actinocrinus Gn part), Hatt 1860 and 1861. 
Calyx more or less depressed, broadly truncate at the base; plates flat 
or nodose, the surface sometimes granulated, but generally smooth. Basals 
short, forming a broad rim, which projects conspicuously outward. Radials 
as large as or larget than both costals together. Costals two, short, wider 
than long; the first quadrangular; the second pentangular or exceptionally 
heptangular. The higher brachials in contact laterally, and forming a 
continuous ring around the calyx. Arm facets directed horizontally; the 
ambulacral openings arranged in groups; respiratory pores well defined. 
Arms from twelve to twenty-six. When there are more than twenty, the 
addition is made in the posterior rays, the other rays having four each. In 
species with less than twenty arms, the anterior ray has the least number. 
Species with sixteen arms always have three in the posterior rays. The 
arms are paddle-shaped, narrow and rounded in the lower parts, broad and 
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