Spirifer iheringi Kayser 

 (See plate 25) 



I, 2 Dorsal aspects of internal casts of young shells 



3 Front view of conjoined valves of a mature individual 



4 Enlargement of surface in a mature valve 



5 A mature dorsal valve 



6 Dorsal view of a characteristic internal cast 



7, 8 The cardinal process in different stages of development 

 Locality: Tybagy, state of Sao Paulo, Brazil 



188 



