1 66 



NEW YORK STATE MUSEUM 

 PLATE 12 



FIG. 



I, 2 



Kionoceras darwini Billings (sp.) 



(See plate io, fig. 22; plate II, fig. 6) 



Page 84 



Two views of a young specimen with excellently preserved 

 surface sculpture 



Fragment showing obscure transverse undulations and alter- 

 nating ribs 



Specimen showing the depth of the camerae and septa 



Originals of fig. 1-4 from Rochester (Arey collection). 



Septal view of individual represented in fig. 6 



Internal cast of older specimen, showing part of the living 



chamber and the increase in the depth of the chambers 

 Internal cast of specimen with gerontic approach of the septa 



and somewhat oblique septal sutures 



