18S8.] 



479 



[Newell. 



The type is Hex. (Phrag.) panderi Barrande (Syst. Sil. n, 

 plate 48). 1 



Hexameroceras delphicolum n. sp. 



Smallest septum. 



Ventral view. 



Aperture. 



Lateral view. 



Compare Hexameroceras (Phragmoceras) callistoma Barr., Syst. Sil. n, p. 



234, pi. 47 and 67. 

 Compare Hexameroceras (Cyrtoceras) Hertzeri H. & W., Pal. Ohio, n, p. 



150, pi. 8, figs. 7 and 8. 



Shell small, arcuate, rapidly enlarging, transverse section broadly 

 ovate ; apex unknown. 



Living chamber is short, its height being two-thirds the greatest 

 dorsi-ventral diameter, the lateral diameter is about nine-tenths of 

 the dorsi-ventral. In general outline the living chamber increases 



1 See. Proc. B. S. N. H., xxn, p. 278. 



