28 
SMITHSONIAN INSTITUTION 
Melocrinus oblongus Wachsmuth and Springer 
Plate 5, figs. 5, 6 
Melocrinus oblongus Wachsmuth and Springer, N. A. Crin. Cam., p. 200, pi. 22, figs. 9, 12. 
Confined to the higher Niagaran beds. Two specimens are figured espe- 
cially to show the division of the rays into two rows of brachials, for compari- 
son with the similar elongate form referred to Roemer’s Cytocrinus with only 
one such row. 
Horizon and locality. Louisville limestone, Louisville, Kentucky, and Bob formation, 
Niagaran; Decatur County, Tennessee. 
Other Niagaran species are M. obconicus Hall, of the Waldron beds, M. aequalis S. A- 
Miller, of the Laurel ; one from Missouri by Rovrley, one from the Racine dolomite of the 
Chicago area and one from the Rochester shale at Lockport. 
Melocrinus onondaga new species 
Plate 5, fig. 4 
I figure here what appears to be a very young stage of the genus from 
the middle Devonian, which is interesting for the remarkable shortness of the 
calyx compared with the well developed arms. 
Horizon and locality. Onondaga formation, Middle Devonian ; Sylvania, Ohio. 
Cytocrinus laevis Roemer 
Plate 5, figs. 7, 70, 8 
Cytocrinus laevis Roemer, Sil. Faun. Westl. Tennessee, i860, p. 46, pi. 4, figs. 2a-c. — Melocrinus roemeri 
Wachsmuth and Springer, N. A. Crin. Cam., 1897, p. 301, pi. 22, figs, iia, b. — Bassler, Bibliogr. Index, 
1915. PP- 795 , 796. 
The brachials in this form are extended into 5 trunks composed of a single 
series of plates, which is a good generic distinction from similar lobate species 
such as Melocrinus oblongus, according to the practice followed in other groups ; 
while the arms themselves have not been seen, the direct succession of primi- 
brachs into the arm opening shows how they must be. 
Horizon and locality. Beech River formation, Niagaran ; Decatur County, Tennessee. 
MARIACRINUS Hall 
Plate 5 
Mariacrinus Hall, Am. Jour. Sci. (2), 25, 1858, p. 278; Pal. New York, 3, 1861, pp. 104, 139. — Wachsmuth 
and Springer, Rev. Pal., 2, 1881, pp. 114, 118, 233; ibid., 3, 1885, p. 326; N. A. Crin. Cam., 1897, 
p. 281. — Zittel-Eastman, Textb. Pah, 2d ed., 1913, p. 190. — Goldring, Devon. Crin. New York, 1923, 
p. 109. — Bassler, Bibliogr. Index, 1915, p. 785. 
BB 4; similar to Melocrinus, but arms free, branching once or twice, with 
alternating pinnules or ramifies. 
Genotype. Mariacrinus plumosus Hall. 
Distribution. Silurian, Devonian ; America, England, Gotland. 
