274 ROBERT TRACY JACKSON ON ECHINI. 



those of the whole spine in mucronata. Shumard and Swallow say the length of primarj' 

 spines is about 2.5 inches, diameter including spinules 0.1 of an inch. 



Middle Coal Measures, Lexington, Missouri; Kansas City, Missouri. Huerco Formation, 

 Diablo Mountains, western Texas, United States National Museum Collection. 



Archaeocidaris ornata (Eichwald). 



Plate 14, fig. 10. 



Echinocrlnus ornatus Eichwald, 1S60, p. 654, Plate 32, fig. 24 (non Archaeocidaris ornafus Newberry, 

 1861, for which see -1. coloradmsi.^, p. 267; non White, 1877, for which see .4. mucronaia, p. 271; non 

 Klem, 1904, p. .54; non Lambert and Thiery, 1910, p. 124, for which see p. 267). 



Known only from primary spines. Milled ring well developed, above which the shaft 

 tapers to the distal end ; the spine is smooth proximally, but distally thickly set with long spinules 

 directed distally at an acute angle. 



Lower Carboniferous, Miatschkowa, near Moscow, Russia. 



*Archaeocidaris ourayensis Girty. 



Phite 14, fig. 11. 



Archaeocidaris ourayensis Girty, 190.3, p. 329, Plate 1, fig. 14; Klem, 1904, p. 63; Lambert and Thiery, 

 1910, p. 12,5. 



Known only from a primary spine, which has a slender axis slightly over 1 mm. in diameter, 

 densely clothed with relatively large and stout spinules du'ected distally. Base and tip of spine 

 unknown. 



Hermosa Formation, Carboniferous (Coal Measures), Ouray, Colorado, holotype, United 

 States National Museum Collection 35,369. 



* Archaeocidaris triplex White. 

 Plate 14, figs. 12a-12c. 



Archaeocidaris triplex White, 1881, p. xxii, Plate 4, figs. 3a-3c; (?) Girty, 1903, p. 330; Klem, 1904, p. 57; 

 Lambert and Thiery, 1910, p. 125. 



Practically known only from interambulacral plates and primary spines. Interambulacral 

 plates described by Dr. White as imperfect, small, thin, only probably belonging to the same 

 species as the spines. Primary spines large, strong, subtriangular in cross section; spinules 

 are strong, short, but prominent and rather distant, in three rows, each upon one of the three 

 obtuse angles of the spine. The rows of spinules extend from a little way above the milled ring 

 to the end of the spine ; the rest of the surface is smooth. 



Carboniferous (Coal Measures), near Taos, New Mexico, cotypes, United States National 

 Museum 9,449; (?) San Juan region. Needle Mountains, Colorado. 



