19 



AKCMOCRINUS ASPERATUS, n. Sp. 



Plate II, Fig. 7, basal view, azygous side below; Fig. 8, summit 

 view, azygous side below and matrix covering some of the 

 plates on the right; Fig. 9, azygous side view. 



Species medium size. Calyx bowl-shaped, subpentagonal in out- 

 line, more than twice as wide as high ; radial ridges interrupted 

 at the sutures ; plates subspinous or very convex and more or less 

 sculptured ; surface granular ; columnar cavity wide, deep, and 

 sculptured so as to indicate a pentagonal column. 



Basals small, deep within the calyx, but not covered by the 

 column, in fact, the column enters the cone formed by the basals 

 leaviDg the basals abutting the subradials outside the circumfer- 

 ence of the column. Subradials large, longer than wide, abruptly 

 bent into the columnar cavity and upward between the radials, leav- 

 ing a transverse ridge across the middle part of each, from each end 

 of which a radial ridge arises, that unites with another in the cen- 

 tral part of each first primary radial. The calyx will rest upon 

 these ridges as the sculpturing is deep. The azygous subradial is 

 octagonal the others are heptagonal, the shorter sides abut upon 

 the basals and adjacent subradials, the longer sides support the 

 radial series while each is rather broadly truncated at the super- 

 ior end. 



Three of the first primary radials are pentagonal, the other two, 

 on the right of the azygous area, are hexagonal. They are all 

 wider than high, the shorter sides abut the interradials, the longer 

 sides the subradials and second radials. The superior side that 

 abuts the second radial is arcnate externally. The inferior angle of 

 each is sunk in a deep pit, the central part of the plate is convex 

 from which a radial ridge extends to each adjacent subradial, while 

 the greatest prominence exists in the upper part. 



Four of the second primary radials are hexagonal and one pen- 

 tagonal, they are of unequal size and vary from a little wider than 

 long to more than twice as wide as long. All of them are longi- 

 tudinally convex in the central part and bear central nodes. The 

 third primary radials are smaller than the second, of unequal size, 

 pentagonal, axillary, and support upon each upper sloping side 

 two small, short, secondary radials before reaching the free arms. 

 The second and third primary radials together are not larger than 

 the first. The radial ridge in each series continues across the 



