Klem — Revision of the Palaeozoic Palae'echinoidea. 51 



11. Archaeocidaris longispinus Newberry. 



1861. Archaeocidaris longispinus. Newberry, Ives' Colo. 



Expl. Exped., pt. 3, p. 116, pi. 1, fig. 1, 1 a. 

 1874. Archaeocidaris longispina. Loven, Kongl. Svens. 



Vetens. Akad. Haudl., Bd. 11, no. 7, p. 44. 

 1889. Archaeocidaris longispina. Miller, N. Amer. GeoL 



Pal., p. 225. 

 1895. Archaeocidaris longispinus. Keyes, Proc. Iowa Acad. 



Sci., vol. 2, p. 191. 

 Primary spines elongate, fusiform, cylindrical in section. 

 Surface smooth or finely striated lengthwise. Basal ring small 

 and crenulated slightly. Spines curve slightly above the ring, 

 otherwise straight throughout. 



Geological formation and locality : Upper Carboniferous, 

 Banks of the Colorado River. 



12. Archaeocidaris megastylus Shumard. 



1858. Archaeocidaris megastylus. Shumard, Trans. St. Louis 



Acad. Sci., vol. 1, p. 225. 

 1874. Archaeocidaris megastylis. Loven, Kongl. Svens. 



Vetens. Akad. Handl., Bd. 11, no. 7, p. 44. 

 1889. Archaeocidaris megastylus. Miller, N. Amer. Geol. 



Pal., p. 225. 



1894. Archaeocidaris megastylus. Keyes, Mo. Geol. Surv., 

 vol. 4, p. 129, pi. 15, figs. 2 a, b. 



1895. Archaeocidaris megastylus. Keyes, Proc. Iowa Acad. 

 Sci., vol. 2, p. 189, pi. 18, figs. 2 a-b. 



1900. Archaeocidaris megastylus. Beede, Univ. Geol. Surv. 

 Kas., vol. 6, p. 49, pi. 8, fig. 7. 



Boss broad and smooth. Areolar surface very broad, 

 slightly coucave at the exterior part and surrounded by a row 

 of small secondary tubercles. 



Primary spines long, robust, fusiform, very finely striated 

 longitudinally and studded with fine granules or minute short 

 spines. Basal ring oblique to the axis with crenulated border. 



Geological formation and locality: Upper Coal Measures, 



