EXPLANATION OF PLATE 13 



Figs. 1-3 Lithostrotion microstylum White; plesiotype ; x5 p. 53 



1, Transverse section of portions of three corallites ; the circular axial column touched 

 only by long septa and the vesicular area between corallites (aphroid) are characteristic. 



2, Longitudinal section of one corallite ; central dark areas are axial column, septa and 

 thickened tabulae ; other dark areas are interrupted epitheca separating adjacent coral- 

 lites ; the raised rim around the axial column is typical. 



3, Longitudinal section of two corallites ; good epitheca is shown at extreme right ; axial 

 column of right polyp shows tabellae and septal lamellae. 



Fig. 4 Favosites divergens White and Whitfield ; holotype ; X 2.5 p. 54 



Longitudinal section ; the sparse mural pores and the occasional oblique tabulae are 

 characteristic. 



Fig. 5 Cladochonus striatus Easton ; paratype ; x 2.5 p. 62 



Section through three corallites encrusting crinoid stem (stippled) which has grown 

 over the coral at two places ; note visceral connection between corallites. 



Fig. 6 Favosites? mancus Winchell ; holotype; x5 p. 54 



Longitudinal section showing sparse mural pores and tabulae. 



Figs. 7, 8 Syringopora harveyi White ; plesiotype ; X 5 . . . p. 61 



7, Transverse section showing spacing of corallites, as well as internal structure. 



8, Longitudinal section showing portion of one septum near upper left edge of section. 



Fig. 9 Pleurodictyum expansum (White); holotype; X 2.5 p. 55 



Longitudinal section ; steeply tilted tabulae in calyx are characteristic. 



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