PLATE 9. 

 Miocidaris keyserlingi (Geinitz). Page 245. 



Fig. 1. Lower Zechstein, Permian, Corbusen, Germany (after Geinitz, 184S, Plate 7, fig. 2). Cotype. Natural size, and 



enlarged. Spine swollen, finely muricate. 

 Fig. 2. Zechstein, Permian, Corbusen, Ronneburg, Germany. Dresden Museum, cotype. X 7.5. Two columns of 



pentagonal plates in an interambulacrum. Redrawn from my sketch of the specimen in the Dresden Museum. 

 Fig. 3. Permian, Humbleton Hill, England. Enlarged, after King, 1850, Plate 6, fig. 22, where in the description of the 



plate this figure, with the two following, are called Palaechinus verneuilianm King, and in the text they are called 



Archaeocidaris verneuUiana King. Cotype of that species (here considered a synonym). 

 Fig. 4. Permian, Tunstall Hill, England. Spine. X 2:8. After King, 1850, Plate 6, fig. 24. Cotype of Archaeocidaris 



verneuUiana King, here considered a synonym. 

 Fig. 5. Probably referable to this species, Permian, Humbleton Hill, England. Enlarged. After King, 1S50, Plate 6, 



fig. 24. Cotype of Archaeocidaris verneuUiana King, here considered a synonym. 



Archaeocidaris wortheni Hall. Page 259. 



Fig. 6. Same specimen as photographs, Plate 8, figs. 5, 6. Cotype. X 1.8. Two columns of plates, all similar, in each 

 ambulacral area and four columns of plates in each interambulacral area from the basicoronal row up. In the basi- 

 eoronal row of the interambulacral areas the plates are nearly or quite whole plates, alternating with half-plates, 

 due to ventral resorption. In areas A and C in this row, the plates of columns 1 and 4 are large and the plates 

 of columns 3 and 2 small. On the contrary, in areas E and G in this row, the plates of columns 1 and 3 are small 

 and the plates of columns 4 and 2 are large. (Compare fig S.) Ventrally pyramids are in place, and ambulacral 

 with interradial non-ambulacral peristomal plates are on the peristome. (Compare text-fig. 26, p. 70.) 



Fig. 7. The same, restored to show a complete peristome and basicoronal row of the corona. X l.S. (Compare text- 

 figs. 47, p. 80; 239 bis, p. 264.) 



Fig. 8. The same restored, showing the ventral border of the corona as in fig. 7, and the plates which havp been removed 

 by resorption restored theoretically. In interambulacral areas A and C, column 4 originates to the right of the 

 center, and in interambulacral areas E, G, and I, column 4 originates to the left of the center, thus producing the 

 system of alternation of large and small plates seen in the basicoronal row of the several areas. (A similar occur- 

 rence of the initial plate of column 4 being on the left of the center, or on the right of the center is seen in 

 MiIdhicIiiiiuh multipnnis, text-fig. 245, p. 382.) 



Figs. 9-11. St. Louis Group, Lower Carboniferous, St. Louis, Missouri. Amer. Mus. Nat. Hist. 7 ",* ' , cotypes, being 



part of the same lot as fig. 6. 



Fig. 9. Plates showing scrobicular ring, basal terrace, primary and secondary spines X 1.9. 



Fig. 10. Pyramid with epiphyses, brace and tooth, the last restored dorsally as indicated by dotted lines. X 3.6. 



Fig. 11. Nearly entire primary spine which is slender, smooth, terete, somewhat arcuate. X 1.9. 



Archaeocidaris legrandensis Miller and Gurley. Page 260. 



Fig. 12. Same specimen as photograph, Plate 8, fig. 7. X 1.8. Four columns of plates in each interambulacral area. 



The plates have a basal terrace well defined (see description of fig. 13). 

 Fig. 13. Same specimen as photograph, Plate 8, fig. 8. X 3.7. Part of the test with smooth, terete primary spines and 



small secondary spines in place. (These two specimens, figs. 12 and 13, are the cotypes of Eocidaris blairi Miller, 



here considered a synonym.) 



Figs. 1-5 drawn by W. M. Barrows; figs. 6-13 by J. Henry Blake. 



