262 ROBERT TRACY JACKSON ON ECHINI. 



Archaeocldaris lacvi^ Trautscholfl, 1879, p. 7, Plate 2, fig. 1 u (the number of the figure is wanting on Plate). 

 Archacocidaris glabrispina Etheridge, 1SS8, p. 221 ; Klem, 1904, p. 62 ; Lambert and Thit'ry, 1910, pp. 124, 125 . 



Primary spines smooth, straight, swollen about the middle, above which tapering to a 

 point. Interambulacral plates hexagonal, about 5.2 mm. wide, and wider than high. 



The species stellifera and laevis may differ from glabrispina if complete material is found; 

 but with present evidence they cannot be distinguished. The plates figured by Baily (my 

 Plate 10, figs. 8a-8c) are so schematic as probably to be unreliable. 



Lower Carboniferous, the original locality given by Phillips is Northumberland; Bundaran, 

 Ireland, in the Griffith Collection, Science and Arts Museum, Dublin (this' is doubtless the 

 material referred to by M'Coy, 1844, p. 173). The specimen figured (Plate 10, fig. 2) is from 

 Hook Head, Ireland, and is in the Sedgwick Museum, Cambridge, England; Clitheroe, England, 

 British Museum Collection E 10,691, this is a small slab with spines and interambulacral 

 plates; Frome, England, a small slab with spines and interambulacral plates, British Museum 

 Collection 38,550; Ireland, from one or more of several localities given by Baily for his A. 

 stellifera, which is considered a synonym of glabrispina, as indeed Baily suggested as possible; 

 Miatschkowa, Province of Moscow, Russia (Trautschold, his A. laevis). 



* Archaeocldaris nerei (Munster). 

 Plate 10, figs. 5a-5d, 6, 7. 



Cidarites nerei Munster, 1839, p. 40, Plate 3, figs. 6a-6d; Koninck, 1842-'44, [description of] Plate E. 



Cidaritcs protci Munster, 1839, p. 40. 



Echinocrinns nerei L. Agassiz, 1841, p. l(j; d'Orbigny, 1850, p. 154. 



Echinocrinus proteih. Agassiz, 1841, p. 16; d'Orbigny, 1850, p. 154. 



Cidaris nerei Koninck, 1842-'44, p. 34, Plate E, figs, la-li. 



Pcdaeocidaris nerei L. Agassiz and Desor, 1846-'47, p. 340. 



Palaeocidari^ protei L. Agassiz and Desor, 1846-'47, p. 340. 



Archacocidaris nerei Miiller, 1857, p. 262, Plate 4, figs. 11, 12a, 12b; Desor, 1858, p. 154, Plate 1, fig. 6; 



Dujardin and Hupe, 1862, p. 465; Loven, 1874, p. 43; Barrois, 1882, p. 321; Julien, 1896, p. 126, 



Plate 6, figs. 6, 7; Lambert and Thicry, 1910, p. 124. 

 Archaeocidaris nerii Klem, 1904, p. 52. 

 Archaeocidaris protei Lambert and Thierj', 1910, p. 124. 



Known fragmentarily, interambulacral plates hexagonal, or pentagonal with rounded 

 adradial border, primary tubercle pronounced, basal terrace marked; around the terrace on 

 the outer portion of the scrobicular area, are numerous fine radial plications; minute secondary 

 tubercles are outside of the scrobicular area. Primary spines cylindrical, vertically finely 

 striate, and as Desor figures them, terminally with well developed spinules directed distally. 

 Miiller figures an excellent pyramid (my Plate 10, figs. 6, 7) which is wide-angled, indicating 

 an inclined lantern, with moderately deep foramen magnum, and laterally with ridges for the 



