EXPLANATION OF PLATE 6 



Figs. 1-3 Clinophyllum chouteauense Miller ; plesiotypes ; X 5 p. 47 



1, Transverse section, early ephebic stage ; note single secondary septum on either side 

 of counter septum ; after Grove. 



2, Transverse section, slightly more advanced than 1 ; tabular intersection across axial 

 region ; counter septum very thick ; cardinal septum thicker than nearby meta-septa ; 

 after Grove. 



3, Longitudinal section ; plesiotype ; note presence of some thickened tabulae. 



Figs. 4-6 Clinophyllum excavatum Easton, n. sp. ; holotype ; University of Missouri No. 1150 ; 



X5 p. 47 



4, Transverse section, late neanic stage ; some septa reach center at transected tabula 

 (dark area). 



5, Transverse section, middle ephebic stage; counter septum thickened; cardinal septum 

 somewhat longer than neighboring meta-septa. 



6, Transverse section, late ephebic stage ; counter septum longest, others about of equal 

 length, though two slightly longer septa may be alar septa ; extraordinarily thick epi- 

 theca is characteristic. 



Ftgs. 7, 8 Cyathaxonia tantilla (Miller); University of Missouri collection ; X 15 . . . . p. 30 



7, Transverse section, early neanic stage. 



8, Transverse section, late ephebic stage ; note carinate septa. 



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