48 



SVEN LOVEN, ECHINOLOUICA. 



terradial plates as well as tliose tliat divide tlie interradial 

 wall, are all distinct.^ 



Discoidea CA-Iindrica Ag. forma vulgaris; the peristome from the inside. 



Anotlier specimen, tlie forma elatior of the same spe- 

 cies,- shows some remarkable difPerences. The branches of the 

 auricles are higher, more free and erect in their iipper por- 

 tions, and present at the top the same slightly tumid pro- 

 jection. The interradial wall which connects their pairs does 

 not reach their height bnt is much lower, and even. The 

 sutures are all obliterated, but a distinct impression marks 

 the limit of the interradial wall toward the branch. When 

 compared in corresponding- parts with the lower form, the diffe- 

 rence is great and almost seems to indicate specific distinction, 

 the more so as at the same time the interradial walls are much 

 narrower and proportionally lower in the elevated form than 



' Compare Duncan and Släden, Linnean Society's Journal. Zoology. XX, 

 p. 48 and Ann. Nat. Historv, September 1889. 



^ CoTTEAU 1. c. pl. lOil f. 1. — Weight 1. C. pl. XL VII. f. 1. 



