1 66 



NEW YORK STATE MUSEUM 

 PLATE ia 



Kionoceras darwini Billings (sp.) 



(See plate 10, fig. 22; plate IX, fig. 6) 

 Page 84 



FIG. 



i, 2 Two views of a young specimen with excellently preserved 

 surface sculpture 



3 Fragment showing obscure transverse undulations and alter- 



nating ribs 



4 Specimen showing the depth of the camerae and septa 



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



5 Septal view of individual represented in fig. 6 



6 Internal cast of older specimen, showing part of the living 



chamber and the increase in the depth of the chambers 



7 Internal cast of specimen with gerontic approach of the septa 



and somewhat oblique septal sutures 



