BATOCRINID &. 495 
has a different arm formula, and the orals are separated from one another by 
supplementary plates. 
Hall's A. pentagonus is undoubtedly synonymous with this species. The 
type specimen is unusually high and narrow, and this accounts for the 
narrowness of its first interbrachial plates. 
Agaricocrinus splendens S. A. Miter. 
Plate XL. figs. 1a, b, ¢. 
1891. S. A. Minter; Journ. Cincin. Soc. Nat. Hist., Vol. XIII., Plate 4, Figs. 1 and 2; also 17th Rep. 
Geol. Surv. Indiana, p. 55, Plate 8, Fig. 10. 
Syn. Agaricocrinus indianensis 8. A. MituER; ibid., p. 53, Plate 8, Fig. 5. 
Syn. Agaricocrinus Gorbyi 8. A. MILLER; ibid., p. 54, Plate 8, Fig. 9. 
Smaller than any other species from the Keokuk group. Calyx depressed 
pyramidal, width and height as five to three, distinctly pentalobate across the 
arm facets, the interradial spaces wide and rather deeply excavated. Dorsal 
cup deeply concave to the top of the first distichals, the second distichals and 
proximal arm plates spreading outward with a slight upward tendency. 
Plates almost flat ; suture lines moderately well marked. 
Basals hidden by the column. Radials small. First costals as large as 
the radials, quadrangular, as long as wide or even longer; the second hep- 
tangular, about as long as the first but considerably wider. Distichals decid- 
edly long for the genus; the second followed by two series of transverse 
arm plates, except in the two posterior rays where in the division approach- 
ing the anal side the arm plates are supported by the first palmar. Arm 
facets contiguous to the second or third arm plate, directed slightly upward. 
Arms twelve, stout at their bases, slender at their tips. _Pinnules long and 
heavy, composed of short joints. Interradial spaces a little sloping, so as to 
give some prominence to the radial portions. First interbrachial elongate, 
rising to the middle of the second costals, where it is followed by two nar- 
row plates of the same length as the first, and a third plate which rests 
between the lateral extensions of the proximal arm plates. First anal plate 
a little longer than the radials; it supports three large plates, of which the 
middle one is longer than the two at the sides; they are followed by a large 
number of irregular rows of from four to five pieces, which form a rounded 
ridge, extending from near the bottom of the calyx to the summit of the 
posterior oral, and which is somewhat inflated in the middle around the anal 
opening. The posterior oral is highly convex, almost as large as the other 
