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506 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
Agaricocrinus bellatrema Hatt. 
Plate XLLI, Figs. 4a, b, ¢, d. 
1861. Aguricocrinus ornotrema* — Hau; Prelim. Descr. New Paleoz. Foss., p. 3. 
1861. <Ayaricocrinus (Amphoracrinus) bellatrena—Hatu; Bost. Journ. Nat. Hist., Vol. VIL., p> 281. 
1877. Amphoracrinus bellatrema —S8. A. Miter; Catal. Amer. Paleoz. Foss., ped: 
1881. Agaricocrinus ornotrema —W. and Sp.; Revision Palsocr., Part IL, p. 112 (Proceed. Acad. Nat. 
Sci. Phila., p. 286), and Whitfield, 1893, Mem. Am. Mus. Nat. Hist. N. York, Vol. I., p. 24, 
Plate 2, Figs. 19, 22. 
Calyx subpyramidal in its anterior aspect; the posterior side inflated and 
strongly protruding; the base completely flat or very slightly convex, and 
distinctly pentangular in outline. 
Basals hidden by the column, the latter resting within a small concavity 
formed by the lower margins of the radials; axial canal pentalobate. Radials 
wider than long. The first costals smaller than the second and quadran- 
gular; the latter about twice as wide as long, pentangular, not larger than 
the radials. Distichals 1 x 2; the plates cuneate, short, and followed by 
two series of short arm plates. Arm facets very large, and those of the 
same ray contiguous up to the third plate. Arms ten, quite heavy at the 
base, but gradually tapering and ending in a sharp point. Pinnules long 
and stout; their joints twice as long as wide. First interbrachials the 
largest plates of the calyx, and the only ones of the dorsal cup which some- 
times are slightly convex; subovate, reaching to one half the height of the 
arm facets, and supporting two narrow pieces, which rise to a level with 
the arm openings. First anal plate longer and generally narrower than the 
radials; the second anal somewhat smaller, the two interbrachials to each 
side of the same form as the corresponding single plate of the other inter- 
radu, but from a third to a half smaller. The next row consists of three 
plates, of which the two outer ones, in part at least, are interambulacral. 
The ventral disk at the posterior side bulges considerably upward and out- 
ward, forming an inflation which, owing to its large size, disturbs consider- 
ably the general symmetry. The median portion of this inflation, the part 
containing the anus, consists of a subovoid, flattened area, which is directed 
obliquely upward. The space is covered by small plates, and thesé in turn 
are surrounded by eight or ten moderately large, strongly nodose or sub- 
clavate pieces, a structure which gives to the anal area, and in fact to the ~ 
* The name Agaricocrinus ornotrema was originally given to this species, but not being properly formed, 
was afterwards changed by Hall to 4. dellatrema. 
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