Favosites turbinatus Billings 



Page 8 



i, 2 Two views of young colony, restored at apex, from section. 

 Shows the extent of covering by opercnla. Natural size. 



3 Opercula. Enlarged x 5. 



4 Calyxes where opercula are removed, x 5. 



5 Section showing open calyxes in the middle and opercula upon 



them on the left, x 5. 



6 Operculum, where the outer smooth layer has been scaled off 



and the interior structure of the operculum is shown, x 7. 



7 Young, still perforated operculum, x 7. 



Devonian : Onondaga limestone, western New York. 



Paropsonema cryptophya Clarke 

 Page 22 



8 Young specimen, preserving interior casts of the first cycle of 



supposed air chambers. Natural size. 

 Devonian: Portage sandstone. West Hill, near Naples, N. Y. 

 The originals of this plate are in the New York State Museum. 



