Genera of the Xorth American Palaeozoic Bryozoa. 521 



Cell apertures in two ranges ; branches 

 carinated ; dissepiments celluliferous 

 and arcuate Septofoba. 



Cell apertures in more than two ranges ; 

 dissepiments arcuate and celluliferous . Synocla.dia. 



Flabellate. 



Cells in two ranges ; median carina ..... Flibelliporina. 

 Cell apertures in more than two ranges; 



no median carina Flabellipjeella. 



Forms having large primary branches, smaller lateral hranches 



Inpundibuliform. 



Cell apertures in two ranges ; median 



carina Ptilopokella. 



Cell apertures in more than two ranges ; 

 no median carina Ptilopoeina. 



Flabellate. 



Cells in two ranges ; median carina Pinnapoeella. 



Cell apertures in more than two ranges ; 

 no median carina Pinnapoeina. 



Branches at nearly right angles : 



Cell apertures in two ranges ; median 



carina Ptilopoea. 



Branches connected hy anastomosis : 



Infundibuliform. 



Cells in two ranges ; median carina Retepoeina. 



Cells in more than two ranges ; no 

 median carina Retepoeella. 



