ad 
= = = > > ~ i = i F > . > ie. a ¥ ¥ 
455 a ‘s = a. = . ~~, C : See pes eo & = ew Pad | [VEA, . | ie ~ a ~ ge s a —> Re 
aa Sa pe Di ‘> - 2 > ~ \ ‘ erie ~ = tif" = 8 a ee iy Bee ne SS 
= Pete cain ecient cmiacinncah remanent acme ———— 
men cee phene ne e oe 
Eat ar ERE — = ae roe abating 9 ee = A: ap See 
i oe aren = = a rit at eon - = a re ae 
— — i 
PLATYCRINID&. 701 
fiemarks. — Resembling P. parvinodus in its general structure, but differ- 
ing in the details. It is readily distinguished by its more elongate form, and 
having the lower brachials to the top of the distichals always preserved in 
the specimens by reason of their sutural union with the interradial plates. 
ORNIGRANULUS GROUP. 
Basals and radials forming a cup with moderately spreading sides, the 
radial facets deep and wide; arms short and very heavy throughout; the 
plates covered with coarse granules or irregular nodes. 
Platycrinus ornigranulus McCuesnevy. 
Plate LXVI. Fig. 8, and Plate LX VIII. Figs. 10a, b, c, 11a, b, and 12a, b. 
1860. McCursnzy; Descr. New Paleoz. Foss., p. 5; and Trans. Chicago Acad. of Sci., p. 8, Plate 5, 
: Fig. 8. 
1881. W. and Sp.; Revision, Part. IL, p. 73 (Proceed Acad. Nat. Sci. Phila., p. 247). 
Syn. Platycrinus nodulosus Hat, 1853 (not Goldfuss, 1833) ; Geol. Rep. Iowa, Vol. I., Part IL. 
p- 541. : 
Calyx of medium size, cup-shaped, moderately spreading; the base but 
slightly convex, the lower part truucated, and the median portions abruptly 
depressed for the reception of the column. Surface of plates entirely and 
| closely covered by small granules of irregular size and form, those nearest 
. the margins smaller and more closely arranged, those surrounding the col- | 
umn facet confluent and more or less ill-defined. Similar granules, but 
smaller, cover the arms, each plate generally having two rows, transversely 
arranged. | 
Basals forming a very shallow saucer, of which the bottom is flattened 
and only the outer margin is visible in a side view; the columnar attach- 
ment circular, and marked by distinct radiating strie; interbasal sutures 
altogether obsolete ; basi-radial and interradial sutures slightly grooved. 
Radials about as wide as long, the sides nearly straight, the width of the. 
lower face nearly equal to the length of the lateral ones, the upper faces at E 
the sides of the facets deeply notched. Facets large, occupying nearly one I: 
half of the width, and fully two fifths the length of the plates; slightly 
thickened around the edges; concave ; directed outward; the margin of the 
face crenulated. Costals triangular, short but wide, covering the whole 
facet; their sloping upper faces concave. Distichals two, the upper one : 
larger than the lower, the latter giving off an arm to the outer side, and | 
