EXPLANATION OF PLATE 7 



Figs. 1-5 Koninckophyllum glabrum Keyes ; plesiotypes p. 51 



1, Transverse section, ephebic stage ; X 2.5 ; median plate with transected tabulae and 

 tabellae bordering it are characteristic ; note septal crests near axis. 



2, Longitudinal section between figs. 1 and 2 ; X 2.5 ; note interrupted median plate. 



3, Transverse section, late ephebic or possible gerontic stage ; X 2.5 ; note absence of 

 median plate or upwarped tabulae and tabellae axially and also withdrawal of septa to 

 periphery ; figs. 1-3 are from same specimen. 



4, Transverse section, early ephebic stage ; X 5 ; note that many septa touch the thick 

 median plate. 



5, Transverse section, very early ephebic or late neanic stage ; X 5 ; most septa touch the 

 very thick median plate ; figs. 4 and 5 are from one specimen. 



Figs. 6-8 Hapsiphyllum (Homalophyllites) pinnitus Easton, n. sp p. 44 



6, Transverse section, early neanic stage ; X 5 ; note lack of tabulae. 



7, Transverse section; ephebic stage; ideotype ; X 2.5 ; fewer septa than typically; 

 6, 7 , are Illinois Geological Survey No. 3502. 



8, Longitudinal section ; paratype ; University of Cincinnati No. 3360a ; note tabulae and 

 solid central area where septa join (open space represents material not preserved in 

 specimen). 



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