BATOCEINID^. 545 



Basals very small, slightly projecting laterally, and notched at the sutnres, 

 the column facet depressed and surrounded by a circular elevated rim. 

 Eadials generally wider than the first anal plate, forming a shallow depres- 

 sion ; the calyx resting iipon the first costals and first interradials. Costals 

 larger than the radials, about as wide as long. Distichals axillary, as large 

 as, or larger than, the second costals ; followed by a row of axillary palmars, 

 and these by a row of post-palmars, which are directed outward, and support 

 eight primary arms to the ray, forming an uninterrupted line around the 

 calyx. Interbrachials : 1, 2, 2, 2, 1, 1, the two upper very small. The plates 

 of the first row, together with the first costals, forming a circlet, around 

 which another circlet is formed by the second row of interradials and second 

 costals. Anal interradius wider ; the first anal supports three plates, which 

 are a little narrower than the single plate at the other sides, and there are 

 4, 5, 3, 2 and 2 pieces above. • Interdistichals two, arranged longitudinally. 

 Tegmen composed of a great number of u-regular pieces. Orals not in con- 

 tact, somewhat larger than surrounding plates, but not otherwise distin- 

 guished; placed between the centre and margin of the tegmen. Anus more 

 excentric than in any other Devonian Megistocrinus, with the possible excep- 

 tion of il/. abnormis. Column unknown. 



Horizon and Locality. — Hamilton group ; Louisville, Ky., and Colum- 

 bus, 0. 



Types in the Lyon collection at Jeffersonville, Ind. 



Remarks. — This species difiers from all others of this genus in having 

 eight primary arms, and in not having them distributed in groups. It has 

 the third bifurcation in the calyx, which in other species takes place in the 

 free arms. 



Miller's Megistocrinus pileatus from Columbus, 0., we take to be identical 

 with this species. That his specimen has but six and seven arm openings in 

 the posterior- rays, while others have eight, proves nothing to the contrary ; 

 the specimen very probably was not quite mature, and represents a transi- 

 tion between our still younger specimen from the same locality with only 

 five and six arm openings to the ray (Plate XLVIII., Fig. 2), and the larger 

 Louisville specimen (Plate XLVIIT., Figs, la, h, c) with eight primary arms 

 all around. 



