276 ROBERT TRACY JACKSON ON ECHINI. 



Archaeocidaris rankini Young. 

 Archaeocidaris rankini Young, 18S2, p. 108. 



Known only from primary spines which bear four rows of spinules or denticles; these are 

 long, thorn-like, and stand out from the shaft at nearly a right angle. This is the only species 

 in which there are four rows of spinules described. No figure has been published. 



Lower Carboniferous shales, Gillfoot, Carluke, Scotland. 



Archaeocidaris prisca (Miinster). 



Cidarites prisons Miinster, 1839, p. 41. 



Eckinocrimts priscus L. Agassiz, 1841, p. 16. 



Palaeocidaris prisca L. Agassiz and Desor, lS4r)-'47, p. 340. 



Echinocrinus prisca d'Orbigny, 18.50, p. lo4. 



Archaeocidaris prisca Desor, 1858, p. 154. 



Archaeocidaris priscus Klem, 1904, p. (i3; Lambert and Thiery, 1910, pp. 124, 125. 



Known only from individual plates and spines. Tubercles sensibly larger than in A. 

 nerei. Primary spines with six granular ridges. No figure has been published. 

 Carboniferous, Regnitzlosau, Belgium. 



Archaeocidaris wervekei Tornquist. 

 Plate 14, figs. 17a-17f. 



Archaeocidaris wervekei Tornquist, 1897, p. 778, Plate 21, fig. 4; Plate 22, figs. 1, 2, 3, 9, 10; (?) Fraipont, 



1904, p. 11, Plate 1, figs. 6, 7. 

 Archaeocidaris werwekei Lambert and Thiery, 1910, p. 125. 



Interambulacral plates are hexagonal, or pentagonal in adradial columns, very high, the 

 height equaling or exceeding the width, basal terrace marked, strong radial plications extending 

 from margins of plates inward. Primary tubercles exceptionally high. Primary spines are 

 incomplete, vertically plicate and finely striate. Nodose eminences are on the ridges between 

 plications. Dr. Tornquist gives a striking and very satisfactory restoration, representing a 

 complete test in side view. In it he shows narrow ambulacral areas, and four columns of plates 

 in the interambulacral areas. The whole test is represented as depressed spheroidal, and I 

 believe is quite correct in form. 



Fusilina Limestone, Lower Carboniferous, Hunsriicken, Alsace, Germany; Lower Car- 

 boniferous, Marbre Noir de Dinant, Belgium (Fraipont). 



* Archaeocidaris urii (Fleming). 

 Plate 14, figs. 16, 18, 19a-19c, 20a-20c; Plate 15, figs. 1, 2a-2c, 3. 



Echinus Ure, 1793, p. 318, Plate IG, figs. 7, 8. 



Cidaris urii Fleming, 1828, p. 478; M'Coy, 1862, (in legend of) Plate 27, fig. 1 (see footnote p. 277). 



