Genera of the North American Palaeozoic Bryozoa. 515 



Fig. 65. Septopora Cestriensis, 2a, Fronds; natural size ; 2b, A portion of the frond e. x4 ; 2c A small 

 portion x8. 



Ltropoka, Hall. 

 (Proc. Amer. Ass. Ad. Sci., Yol X, p. 179. 1857.) 

 Type, Zyropora lyra^ Hall. 



" Bryozoiim consisting of reticulated, foliated expansions, mar- 

 gined on either side by strong, ''stony supports, which diverge 

 from the base curving upwards and outwards." 



Fio. 66. Lyropora ranosculum. The thickened margin, natural size and transverse section of same. 

 FiQ. 67. Noncelluliferous f ace of a f rond, x9. 

 Fia. 68. CelluUferous face, xl8. 



