502 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
bulacral pieces, with occasionally a larger covering plate among them. 
Interambulacral plates very numerous and comparatively flat; anal open- 
ing lateral. 
Horizon and Locality — Keokuk group ; Indian creek, Montgomery Co., 
Ind. 
Types in the collection of Wachsmuth and Springer. 
Liemarks. — The specimen on Plate XXXIX., Fig. 7, is exceedingly inter- 
esting as having on three of its arms well defined cysts, similar to those pro- 
duced in recent Crinoids by Myzostoma, and it appears as if portions of the 
parasites are still preserved on the fossil. This is the first instance where 
such cysts have been noticed on the arms of Paleozoic Crinoids. 
Agaricocrinus inflatus Hatz. 
Plate XLI, Figs. La, b, ¢, d. 
1861. <Agaricocrinus inflatus — Hauu; Prel. Des. New Pal. Foss., p. 4. 
1861. <Aygaricocrinus (Amphoracrinus) tnflatus —Hatu; Bost. Journ. Nat. Hist., Vol. VIL. p. 284. 
1877. <Amphoracrinus inflatus —S. A. Minter; Catal. Amer. Paleeoz. Foss., p. 70. 
1881. <Agaricocrinus inflatus —W. and Sp.; Revision Paleocr., Part II., p. 112 (Proceed. Acad. Nat. Sci. 
Phila., p. 286). 
A robust species, in form approaching Amphoracrinus ; the symmetry 
extremely irregular. Calyx as high as wide and obscurely pentalobate; the 
interradial spaces at the arm regions slightly impressed. The whole lower 
face of the calyx flat or concave ; the second interbrachials, the upper edges 
of the first, and the arm facets the only parts of the dorsal cup visible 
in a side view. Ventral disk highly elevated, broad at the top, and enor- 
mously inflated at the posterior side. The plates throughout the calyx 
are but slightly convex, barely enough to bring out distinctly the suture 
lines ; only the posterior oral is more or less nodose, and sometimes 
subspinous. 
Basals hidden within the column concavity; axial canal sharply pen- 
tangular. Radials a little wider than long, the sides rapidly spreading, the 
lower end thickened, forming a circular ridge around the columnar depres- 
sion. First costals fully twice as wide as long, quadrangular, three of their 
sides convex, the upper straight. Second costals wider, and sometimes longer 
than the first, the sides spreading abruptly. Distichals 2 2; the plates 
short and cuneate, meeting laterally with their pointed ends, their wider 
faces directed to the outer sides of the rays, whereby the facets of the con- 
fluent arms are brought into an even line; contrary to the case of other 
