J73. CONTRIBUTION TO 



The basal plates form a slight rim. The stem is rather large and the 

 perforation round. 



All of the radial plates are somewhat wider than long, a very little convex 

 and all connected by a slight line. 



The first interradial plate is the largest plate on the dorsal cup and about 

 as long as wide, a little convex and with the slightest appearance of radiating 

 ridges. Above this plate are two smaller ones, and two yet smaller above the 

 latter two. 



There are nineteen arm bases with two pairs of respiratory pores for each 

 arm group or tM'enty in all. 



The arm groups are somewhat lobed in this form, unlike the previously 

 described forms. 



The plates of the ventral disk are convex and each with a small central 

 nipple like spine. 



Tlie anal tube is only moderately strong, and with convex plates bearing 

 central nodes. 



The first plate of the anal area is a little longer than the first radial plate, 

 and supports above three rather large plates. Above these latter, appear to 

 be two smaller plates. 



Horizon, locality and collection same as the last. 



BATOCRINUS ICOSIDACTYLUS, Casseday, Rowley. 



Plate 51. Figs. 16, 17, 18. 



The three basal plates of this species form rather a strong rim. The col- 

 umn is not large and the perforation small. Outside of the basal plates the dor- 

 sal cup forms the frustrura of a very low cone. All of the calyx plates are con- 

 vex merely and all of the radial plates much wider than long. In each radial 

 ray there are two bifurcations, making twenty arm bases in all. 



Above the second bifurcation are three plates to the periphery. 



The interradial plates are one large one below, two smaller ones above and 

 a yet smaller one above the two. 



The arm bases form a continuous rim. 



There are apparently two respiratory pores to the arm base. 



The ventral disk is deeper than the dorsal cup and the plates are convex, 

 some of them bearing short, stout spines. The arrangement of these spines 

 seems to be three in a triangular form above each arm group and one above the 

 anal area, with a semicircle of large ones above, on the anterior side of the 

 vault. 



