ACTINOCRINID 2. O91 
suture, and support the free arms. There are but two primary arms to each 
ray, which branch three or four times at irregular intervals, the first bifurea- 
tion taking place above the fifth to sixteenth double row of ossicles, the last 
a short distance from the tips. Arms divergent, rather stout, and tapering 
very little; they are cylindrical, and above the second plate biserial, the two 
proximal ones of the primary arms being cuneate. First interbrachials of 
moderate size, rising to the height of the second costals; the two plates of 
the second row are to a large extent interambulacral, touching the distichals 
but slightly at their lower ends. Anal plate a little longer than the radials, 
and nearly as wide ; followed by three plates, of which the two outer ones 
are as large as the single plate of the regular sides, the middle one smaller 
and cuneate. The tegmen is not shown in any of the specimens, being cov- 
ered by the arms, but apparently it had no spines, or the points would be 
visible at the ends of the arms. 
Horizon and Locality. — Waverly group; Richfield, Summit Co., Ohio. 
Types in the New York State Cabinet at Albany, N. Y. 
Amphoracrinus spinobrachiatus (Ha11.). 
late EXON igs oe, 
1860. <Actinocrinus spinobrachiatus — Hau; Suppl. Geol. Rep. Iowa, p. 6. 
1873. Amphoracrinus (?) spinobrachiatus —Murxk and Wortuen; Geol. Rep. Illinois, Vol. V., p. 389, 
Plate 6, Figs. 5a, 0, ¢. 
1881. Amphoracrinus spinobrachiatus — W. and Sp.; Revision Paleocr., Part II., p. 155. 
Syn. Actinocrinus inflatus Haut; 1860, Suppl. Geol. Rep. Iowa, p. 20. 
Syn. Amphoracrinus inflatus — WuitriELD; Mem. Amer. Mus. Nat. Hist. N. York, Vol. I., p- 22, 
Plate 2, Figs. 10, 11 (not Actinocrinus (Amphoracrinus) inflatus Hall, 1861, Boston Soc. Nat. 
Hist., p. 284 == Agaricocrinus inflatus). 
Calyx subpyramidal, distinctly lobed; the dorsal cup shallow-saucer- 
shaped ; almost flat, and in specimens with the arms preserved not visible 
from a side view. Ventral disk nearly as high as its width at the arm bases, 
inflated above the food grooves, and the lower part of the interambulacral 
spaces depressed. The plates of the dorsal cup thin, their surface covered 
with irregular, rather prominent rugosities, which are confluent, arranged in 
rows, and form transverse ridges. The ridges upon the radials are crescent 
shaped; those of the first costals straight, while those of the second costals 
and distichals are angular, their salient angles directed upwards, the ridges 
upon the interbrachials less distinct, and longitudinally arranged. 
Basals forming a hexagonal, slightly projecting disk, which extends but 
