452 THE CRINOIDEA CAMEEATA OF NORTH AMERICA. 



short, transverse node, and the lower portions of the first interbrachials are 

 slightly thickened. 



Basals large, constituting a short cylindrical cup, fully twice as wide as 

 the column, sometimes slightly expanding at the lower end, and hexagonal 

 in outline. Radials much larger than the two costals together, wider than 

 long, the lateral faces considerably longer than the sloping upper ones, the 

 upper faces slightly concave. First costals quadrangular, one third wider 

 than long ; the second pentangular, wider and longer than the first. Dis- 

 tichals 2X2 throughout the calyx, but those of the anterior ray are suc- 

 ceeded directly by the arms ; while in the posterior rays, in the division next 

 to the anal side, and in both divisions of the antero-lateral rays, the second 

 distichals are axillary, and support a palmar from each side. Arm openings 

 directed slightly upwards ; almost equidistant ; the arm-bearing plates in 

 contact laterally, except those facing the anal side, which are separated by 

 a narrow, elongate plate. Arms sixteen, moderately long, rounded on the 

 back, gradually tapering to the tips, and composed from their bases up of 

 two series of rather long pieces. Pinnules long, the joints elongate. Inter- 

 brachials two to three, those of the second row comparatively large. At the 

 anal side also, the upper plates are large for this genus ; the anal plate is 

 higher than the radials, and succeeded by three plates, which are as high and 

 almost as wide as the corresponding single plate at the other sides ; the three 

 plates of the second row are fully as large as the axillary distichals. Ventral 

 disk conical, the plates large, nodose, and extended into a long central tube, 

 ■which reaches far beyond the tips of the arms. The tube is stout at the 

 base, but gradually tapers to a sharp point at the end, and is composed of 

 similar plates as the disk. The posterior oral is pushed far out to the an- 

 terior side ; it is three times as large as the four others, more prominent, and 

 arranged transversely. Column small, the nodal joints rather high, with 

 rounded edges, and wider than the intervening ones. At 4 cm. from the 

 calyx the last internode contains seven pieces. 



Honzo7i and Locality. — Keokuk group; Indian creek, ten miles from 

 Crawfordsville, Montgomery Co., Ind., where it was found by us in large 

 numbers and in excellent preservation. 



Remarks. — Baiocrinus agnatus S. A. Miller, is identical with this species, 

 with only two arms in the anterior ray in place of three. 



