BATOCRINID&. | 501 
contact with the others. The radial dome plates as large as the orals, and 
represented in the posterior rays by plates of a first and second order, in the 
other rays by a primary plate only. Interambulacral spaces depressed, the 
plates almost flat. Column proportionally large. 
Horizon and Locality. — Keokuk group; Keokuk, Iowa, and Niota, Ills. 
Type in the collection of Professor Wetherby. 
Remarks. — Wetherby’s description is so general and indefinite, that a 
satisfactory identification of the species is impossible without a comparison 
with the type, which is not available at present. 
Agaricocrinus conicus W. and Sp. (nov. spec.). 
Plate XX XIX. Figs. 7, &. 
Of medium size. Calyx conical, rather high, width and height as 6 to 5; 
in its dorsal aspect irregularly pentalobate, the recess between the posterior 
rays twice as wide as between the others, and the rays themselves stronger 
and projecting out farther. Dorsal cup moderately excavated to the middle 
of the first costals; plates slightly convex; suture lines distinct. 
Basals concealed by the column. Radials varying in size, the two poste- 
rior ones. larger than the others. First costals considerably wider at the top 
than at the bottom, their length equal to, or exceeding, the lower width; three 
of them hexangular, the two posterior ones pentangular. Second costals pen- 
tangular, as long as the radials and twice as wide; the posterior ones hexan- 
gular. The distichals in the posterior rays consist of a single plate, which is 
as large as the second costals, and axillary; supporting 2 X 2 palmars, which 
are twice as long as the arm plates. Rays with but two arms have two suc- 
cessive distichals, which in form and size resemble the palmars. Arm facets 
directed horizontally, contiguous to the second row of arm plates. Arms 
broadly spreading, and moderately heavy at their bases. Interbrachials short, 
rarely reaching the top of the first costals; the two plates of the second row 
as long as the first, and almost as wide, the three of the third smaller. First 
anal plate smaller than the posterior radials, but shorter than the second 
costals ; the interbrachial plates enclosing the latter rather large, rising to 
the second costals; they are followed by three as wide but somewhat shorter 
plates, and numerous others, which together form a flat area with a slight 
swelling around the anus. Posterior oral as large as the others together, and 
in contact with them. The food grooves hidden by superimposed interam- 
