ARCHAEOCIDARIS. 269 



Warsaw Limestone, Lower Carboniferous, Warsaw, Illinois, American Museum of Natural 

 History; Keokuk Limestone, LaGrange, Lewis County, Missouri. An Archaeocidaris sp. 

 that approaches shumardana, Lower Carboniferous, Eureka District, Nevada (Walcott). 



*Archaeocidaris edgarensis Worthen and Miller. 



Plate rS, figs, lla-llc, 12-14. 



Archaeocidaris edgarensis Worthen and Miller, 1883, p. .337, Plate 30, figs. 1.5a-1.5c; Keyes, 1891, p. 245; 

 Klein, 1904, p. 4S; Lambert and Tliiery, 1910, p. 124. 



Known only from dissociated plates, spines, and jaws. Interambulacral plates, as figured 

 by Worthen and Miller, hexagonal, the height and width about equal. They do not show the 

 basal terrace or scrobicular area clearly; this is probably due to the wear of specimens. Pri- 

 mary spines long, tapering, slightly constricted above the milled ring, smooth proximally, 

 above which thickly set with short spinules pointing distally. Portions of jaws associated with 

 spines of this species are from Manhattan, Kansas. As seen in Plate 13, figs. 12-14, the 

 pyramid is wide-angled, foramen magnum moderately deep, ridges exist laterally for the 

 attachment of interpyramidal muscles. In an inner view (Plate 13, fig. 14) the dental slide 

 is seen, but it does not reach the base of the foramen magnum, a general Palaeozoic character. 



Upper Coal Measures, Carboniferous, near Baldwinsville, Edgar County, Illinois. Type from 

 this locality given as no. 2,447, in Illinois State Collection; Lower Coal Measures, Des Moines, 

 Iowa; Junietta Group, Manhattan, Kansas, J. W. Beede Collection. 



*Archaeocidaris newberryi Hambach. 



Plate 8, fig. 9; Plate 13, figs. 15a, 1.5b. 



Archaeocidaris newberryi Hambach, 1884, p. 551, Plate D, fig. 1; Keyes, 1894, p. 129; 1895, p. 187; Klem, 

 1904, p. .53; Lambert and Thiery, 1910, p. 125. 



Incompletely known. lAmbulacral plates wide, low, with lateral bevel which would pass 

 under the adradials as known in other species. Interambulacral plates hexagonal, wider than 

 high, basal terrace marked, secondary tubercles with some small secondary spines in a narrow 

 row along margin of plates. Primary spines very long up to or exceeding 57 mm. in length, 

 slender, tapering throughout, with numerous fine sharp spinules pointing distally, and falling 

 in definite parallel series. 



Lower St. Louis Limestone, Lower Carboniferous, St. Louis, Missouri. The holotype 

 from the Hambach Collection is now in Mr. F. Springer's collection, no. 8,119. 



*Archaeocidaris trudifer White. 

 Plate 13, figs. 16a, 1Gb. 

 Archaeocidaris trudifer White, 1874, p. 17; 1876, p. 89; 1877, p. 104, Plate 6, figs. 8a, 8b; Keyes, 1895, 



