IOWA ACADEMY OF SCIENCES. 
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Archa:ocidaris triplex White. 
Arclmocidaris triplex White, 1882; Rep. Garb. Invert. New Mex- 
ico, p. 22. 
Horizon and localities. Carboniferons, Upper Coal Measures: 
New Mexico. 
Archa:ocidaris ornatus Newberry. 
Archceocidaris cnmatus Newberry, 1861; Ives’ Expl. Colorado 
River, p. 116. 
Arch ocularis ornatus White, 1877; U. S. Geog. Sur. w. 100 
Merid., vol. IV, p. 104, pi. vi, fig. 7. 
Only spines and an imperfect interambulacral plate known. 
The former are much stouter and spinous projection much 
larger than in A. longisjnnus. 
Horizon and localities. Carboniferous: Ojo del Oso, New 
Mexico. 
ARCHmOCIDARIS TRUDIFER White. 
Archceocidaris trudifer White, 1874; Expl. and Sur. w. 100 Merid., 
Prelim. Rep. Invest. Fossils, p. 17. 
Archceocidaris trudifer White, 1877; U. S. Geog. Sur. w. 100 
Merid., vol. IV, p. 104, pi. vi, figs. 8n-?>. 
Similar to A. megastylus, but with spines more slender, and 
spinous processes smaller; interambulacral plates much smaller. 
Horizon and localities. Lower Carboniferous : ‘ ‘Camp Apache, ” 
Arizona. 
ARCHmociDARis LONGiSPiNus Newberry. 
Archceocidaris, looigisjnnus Newberry, 1861; Rep. Colorado River 
of West, Ives’ Exp., p. 116, pi. i, figs. 1-la. 
Spines only known, long, straight, with small granulations 
as spinous processes. 
Horizon and localities. Carboniferous: Juncture of the two 
Colorado rivers, Arizona. 
Perischodomus?? illinoisensis Worthen & Miller. 
Perisclwdomus illinoisensis Worthen & Miller, 1883. Geol. Sur. 
Illinois, vol. VII, p. 333, pi. xxxi, fig. 8. 
Test small. Interambulacral plates in five to seven rows. 
Horizons and localities. Carboniferous, Kaskaskia limestone: 
Bay City, Pope county, Illinois. 
The species is too poorly defined to enable the characters to 
be made out with certainty and the figure of the type shows 
