Netc Species of Fossih f rum Ohio. 'l\\^ 



size, tlie larger individual plates being mure than an inch in 

 transverse diameter, while the species above referred to is minute. 

 The (!ccurrence of forms of this genus m rocks of Devonian age 

 is also a new feature in its history ; as those of Europe are con- 

 fined to the Lower Silurian formations and the lower, beds of 

 the UpjDcr Silurian ; while these occur above the middle Devo- 

 nian. 



Formation and Locality. — In the Huron shale at Sheiheld and 

 Birmingham, Erie Co., Ohio ; equivalents of the Genesee slates 

 'and Portage group of New York. 



The followinj^ species are from the Maxville limestone of 

 Maxville, IVewtoDTllle, and the neighboring parts of Ohio, 

 equivalent to the Chester limestone, or Chester and St. Louis 

 limestones, of the lYlississippi Vallej. 



CEINOIDEA. 

 Cyalhocriniis incquidactjlu^i, u. sp. 



Pal. O., Vol. Ill, Plate 9, Figs. 5—8. 



Body of rather small size. Calyx deep cyathiform, being nearly hemi- 

 spherical in one example, and somewhat broad obconical in another, and 

 composed of smooth plates, which have only the general convexity of the 

 the body, or very slightly tuberose. Basal plates minute to moderate size, 

 higher than wide. Sub-radials large ; height and width nearly equal ; two 

 of thena heptagonal and the others hexagonal, the lower sides barely diverg- 

 ing from a straight line. First radials wider than high, and about two-thirds 

 as high as the sub-radials. Anals visible, three in number; the first elongate 

 pentagonal, nearly twice as high as wide, and situated a little obliquely on 

 the right side of the area ; the other two are small and pentangular. Second 

 radials, or first arm-plates, smaller than the first radiats and narrowing up- 

 ward, wedge-formed above, and each supporting Iwo arms. On the pos- 

 tero-lateral rays they are long and cylindrical, with the arms slender. On 

 the anterior ray it is short and supports two slender arms ; while on the 

 antero-lateral rays they support a slender arm similar to those of the other 

 rays on the anterior side, and on the outer side an arm several times larger 

 and stronger than the others, and composed of larger and stronger plates. 



Plates of the arms short and unequal-sided, and giving origin to jointed 

 tentacula from the longer side of each plate, which is upon the alternate 

 sides of the arm, or on the same side from every second plate. Surface of 

 the plates smooth. Length of the arms and subsequent bifurcations not 

 known. Column small, round, and composed of unequal-sized plates alter- 

 nating with each other. 



The slender arms are preserved on two individuals to the length of about 



