738 THE CRIlSrOIDEA 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 

 Co., N. Y. 



COCCOCRINUS MiTLLEE. 



1855. JoH. MuLLEE; Verb. Naturliist. Verein Klieiiilande, Vol. XII., p. 20. 



1857. Pictet; Traite d8 Paleont., Vol. IV., p. 310. Plate 100, Fig. 3. 



1860. F. Roejirr; Foss. Fauna West. Tennessee, p. 51. 



1862. DujAKDiN and Hope ; Hist. Natur. des Zoophytes, p. 107. 



1879. ZiTTEl ; Haudb. der Palseont., Vol. I., p. 347. 



1881. W. and Sp., Revision, Part 11., p. 58 (Proceed. Acad. Nat. Sci. Phila., p. 232). 



1844. P. Herb. Carpester; Cliallenger Rep. of tlie Stalked Crinoids, pp. 160 to 163. 



1885. W. and Sp.; Revision, Part III., p. 114 (Proceed. Acad. Nat. Sci. Pliila., p. 336). 



18S7. W. and Sp. ; Proceed. Aead. Nat. Sci. Pliila., p. 22. 



1889. Neumayr; Stamme des Thierreiclies, p. 470. 



1890. S. A. Miller; North Amer. Geol. and Palajont., p. 232. 



Syn, Ptati/eritms (in part) Roemek; Rliein. Uehergangsgeb., p. 63, Plate 3, Fig. 3. 



Coccocrinus is the simplest possible form o£ the Camerata, the calyx 

 consisting only of three basals, five radials, two costals, five small inter- 

 brachials and five orals. As in Flatt/crimis, 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 Platycrinid^, 

 and excavated at the upper end to form a facet for the reception of the 

 costals, which consist of two short, transverse plates (not of one as here- 

 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 

 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 

 Eifel, Germany. 



