BATOCRINID&. «545 
Basals very small, slightly projecting laterally, and notched at the sutures, 
the column facet depressed and surrounded by a circular elevated rim. 
Radials generally wider than the first anal plate, forming a shallow depres- 
sion; the calyx resting upon 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 irregular 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 M. abnormis. Column unknown. 
Horizon and Locality. — Hamilton group; Louisville, Ky., and Colum- 
bus, O. 
Types in the Lyon collection at Jeffersonville, Ind. 
Remarks. — This species differs 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, O., 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 XLVUL, Fig. 2), and the larger 
Louisville specimen (Plate XLVIIL., Figs. 1a, 8, c) with eight primary arms 
all around. 
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