—— or 
738 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
the second costals, and again from the tenth distichal. Arm joints wider | 
than long, rounded on the back, and with strong pinnules composed of joints 
a little longer than wide. Column round, rather large, the joints growing 
thicker downward. Cirri have not been observed. 
Horizon and Locality. — Upper Helderberg group; Schoharie, Herkimer 
Conan. 
COCCOCRINUS Mutter. 
1855. Jou. Mitten; Verh. Naturhist. Verein Rheinlande, Vol. XII., p. 20. 
1857. Pictur; Traité de Paléont., Vol. IV., p. 310, Plate 100, Fig. 3. 
1860. F. Rormer; Foss. Fauna West. Tennessee, p. 51. 
1862. Dusarpin and Hur; Hist. Natur. des Zoophytes, p. 107. 
1879. Zitren; Handb. der Paleont., Vol. I., p. 347. 
1881. W. and Sp., Revision, Part II., p. 58 (Proceed. Acad. Nat. Sci. Phila., p. 282). 
1844. P. Hers. Carpenter; Challenger Rep. of the Stalked Crinoids, pp. 160 to 163. 
1885. W. and Sp.; Revision, Part ILI., p. 114 (Proceed. Acad. Nat. Sci. Phila., p. 336). 
1887. W.and Sp.; Proceed. Acad. Nat. Sci. Phila., p. 22. 
1889. Nzumayr; Stamme des Thierreiches, p. 470. 
1890. S. A. Mitter; North Amer. Geol. and Paleont., p. 232. 
Syn. Platycrinus (in part) Ropmer; Rhein. Uebergangsgeb., p. 68, Plate 3, Fig. 3. 
Coccocrinus is the simplest possible form of the Camerata, the calyx | 
consisting only of three basals, five radials, two costals, five small inter- 
brachials and five orals. As in Platycrinus, two of the basals are larger and | 
equal, and the third, which is but half the size of the others, has the same 
orientation as in that genus. The radials are large, as in all Platycrinide, 
and excavated at the upper end to form a facet for the reception of the 
tofore supposed), The upper costal is axillary, and supports two arms, 
which. apparently were delicate. The interbrachials rest at all sides upon 
the truncated upper angles of the radials, and against both costals. The 
ventral disk is covered entirely by five large orals which slightly touch the 
radials; they meet in the centre, but are parted on approaching the arm 
bases, where they leave narrow slits, at the bottom of which small portions 
' 
: 
costals, which consist of two short, transverse plates (not of one as here- | 
| 
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of the disk ambulacra make their appearance ; while they are at the upper | 
end altogether subtegminal. The lower margin of the posterior oral, and | 
the upper of the interbrachial plate below, are deeply excavated, and form | 
a large, circular anal opening. Column round. | 
/ 
Distribution. — Two species have been described, one from the Niagara | 
group of Western Tennessee, the other from the Middle Devonian of the 
Kifel, Germany. 
