Geneea of the JSJ'orth American Palaeozoic Bryozoa. 505 



projections from adjacent carinae unite and form solid connections 

 of the two carinae. 



The carinae of this genus vary in the same manner as do those 

 of Fenestella, and from these variations the species are divided 

 into several groups, corresponding to, and designated by the 

 same letters as the groups of Fenestella. 



Figs. 44-50. Ctcloporina, showing various forms of the carina. 



Figs. 44, 45, 46. Showing the carinee of the species of this genus ; viewed from 



Figs. 47. Illustrating the carinee of group y. 



Fig. 48. Illustrating carinae of group £. 



64 



