ECHINOIDS. 129 



Archseocidaris newberryi Hambacii. 



Archccocidaris neioberryi Flambacb, 1884: Trans. St. Louis Acad. Sci., 

 vol. IV, p. 551, pi. D, tig. 1. 



Very closely related, and probably identical with, A. sJiu- 

 mardana. 



Horizon and localities. — Lower Carboniferous, Lower St. 

 Louis limestone: St. Louis. 



Archaeocidaris norwoodi Hall. 



Archceocidaris norwoodi Hall, 1858: Geol. Iowa, vol. I, p. 701,pl. xxvi, 

 figs. 5a-e. 



Interambulacral plates with smaller tubercles than in A. 

 agassizi. Spines small, slender, with sharp, scattered spinous 

 processes on the upper half. 



Horizon and localities. — Lower Carboniferous, Kaskaskia 

 limestone : Kaskaskia (Illinois). Reported also from near St. 

 Louis. 



Archaeocidaris halllanus ( Geinitz). 



Eocidaris hallianus Geinitz, 1866: Garb, und Dyas in Nebraska, p. 61, tab. 



V, figs. la-b. 

 Eocidaris hallianus Meek, 1872: U. S. Geol. Sur. Nebraska, p. 152, pi. vii, 



figs. 9a-d. 



A very small form, with spines about a centimeter in 

 length. 



Horizon and localities. — Upper Carboniferous, Upper Coal 

 Measures : Kansas City. 



If the identification of the Kansas City specimen is cor- 

 rect, it seems probable that this form should more properly 

 come under Archaeocidaris rather than Eocidaris. 



Arciiaeocldaris megastylus Shumard. 



Plate XV, figs. 2a-l). 



Archceocidaris megastyliis '&h.\im.&xd,\8b8: Trans. St. Louis Acad. Sci., vol* 

 I, p. 225. 



Known only from loose spines and plates. Interambula- 

 cral plates very large and heavy, hexagonal, margins slightly 

 turned upward ; central tubercle large, considerably elevated; 



