182 
IOWA ACADEMY OF SCIENCES. 
Melonites grasses Hambach. 
Melonites crassus Hambach, 1884; Trans. St. Louis Acad. Sci., 
vol. IV, p. 548, pi. C, tig. 1. 
Melonites crassus Keyes, 1894; Missouri Geol. Sur., vol. IV, p. 
126. 
Closely resembles M. multipora, but with only five rows of 
interambulacral plates, the latter being also larger and covered 
with larger spines. 
Horizon and loccdities. Lower Carboniferous, St. Louis lime- 
stone: St. Louis, Missouri. 
Oligoporus nobilis Meek & Worthen. 
Oligoporus noMUs Meek & Worthen, 1868; Proc. Acad. Nat. Sci., 
Phila., vol. XIX, p. 358. 
Oligoporus nobilis Meek & Worthen, 1873; Geol. Sur. Illinois, 
vol. V, p. 476, pi. xi, fig. 3. 
Somewhat larger and heavier than 0 . multipora, but with 
fewer ranges of interambulacral plates, which are also much 
larger; apical portions very similar. 
Horizon and loccdities, Lower Carboniferous, Burlington 
limestone: Calhoun county, Illinois. 
Oligoporus dan^ Meek & Worthen. 
3Ielonites dance Meek & Worthen, 1860; Proc. Acad. Nat. Sci., 
Phila., vol. XI, p. 397. 
Oligoporus dance Meek & Worthen, 1866; Geol. Sur. Illinois, vol. 
II, p. 249, pi. xvii, fig. 8. 
Oligoporus dance Keyes, 1894; Missouri Geol. Sur., vol. IV, p. 
126, pi. xvii, figs. 2a-b. 
Test large, spherical. Interambulacral areas lanceolate in 
outline, moderately convex, occupied below the middle by nine 
vertical ranges of plates. Ambulacral areas about half as wide 
as the others, and nearly as convex, the broad, rounded furrow 
on each side of the middle rather shallow. Pore plates in four 
rows, much wider than high, and somewhat irregular. Surface 
covered with small tubercles at the spine bases. 
Horizon and loccdities. Lower Carboniferous, Keokuk lime- 
stone: Felton (St. Louis county) and Curry ville (Pike county) 
in Missouri; Keokuk, Iowa; Warsaw, and in Jersey county, in 
Illinois. 
