Box 25, Folder 13: Paleontology Notes 5? - Crinoidea B

Macrostylocrinus ornatus, Hall, Pal. of N.Y. Vol. 2 p. 204 pl. 46 fig. 4

Body small, composed of three pelvic plates of moderate size, succeeded by five large costal plates, three of which are heptagonal and two are hexagonal, hav= ing all truncated upper margins on which rest the scapular plates, and to which succeeds in each series a single arm plate; a single hexagonal or heptagonal interscapular plates is interposed between the scapular plates, its lower oblique edges resting on the short oblique upper edges of the costal plates; the interscapular plate supports two small plates above it, which are succeeded by other by other small plates; each arm=plate supports upon its oblique upper edges a pair of arms, which diverge from each other; each arm in its lower part is formed of a single series of eight or nine plates, above which it is composed of a double series slightly interlocking with each other; surface

of plates of the body tuberculo=striate, the lower ones being marked with interrupted ridges or striae with few tubercles, while the upper ones, or the scapular, interscapular and arm plates, are covered with minute tubercles, sometimes elongated in a direction from the centre to the upper and lateral margins; two or three of the lower simple joints of the arms are tuberculate or cren= ulate on the upper margins, while the upper or double series of plates of the arms are marked by distinct round or sub= angular tubercles along the centre.

L. 0.5 D 0.65

Middle Silurian -Niagara Shale

Lockport N.York

Genus

Mariacrinus Hall Am. Jour 2d Ser 25 p 278 (1858)

Genus

Megistocrinus, Owen + Shumard

(1852) Geol Rep. of Wis. Iowa +c p. 594

Megistocrimis Evansii Owen + Shum.

Geol Rep. of ^Wis Iowa +c p 594 pl 5 A fig 3

Carb. Limestone

Burlington Iowa

Encrimtal Limestone, Monmouth Ill