BRYQZOA—CRYPTOSTOMATA. 



145 



LII. Fenestrapora Hall. 



Differs from Semicoscinium, in the reverse of the zoarium and the 

 expanded summits of the carinae being furnished with large scat- 

 tered pores or pits. Devonic. 



92. F. occidentalis Ulrich. (Fig. 201, e.) Devonic. 



Fenestrules oval ; carina angular and expanded ; the irregu- 

 larly disposed pits on the side, rather few in number ; frond rather 

 coarse. 



Hamilton of Iowa. 



LIII. Unitrvra Hall. 



Differs from Fenestella in having the prominent carinae thick- 

 ened above and connected by thin, oblique, subimbricating plates 

 (scalae) varying from two to each fenestrule to the number of zocecia. 

 Sil.-Dev. 



93. U. scalaris Hall, (Fig. 202, a-g.) 



Devonic. 



Fig. 202. Unitrypa scalaris. a, fragment of carinae and scalae ; 6, summits of car- 

 inas and scalae, showing nodes on former, X 4 '■> c > fragment showing thin carinae and 

 scalae, X 4 '■> d> fragment showing under side of carinae and scalae, X 4 5 e , /> transverse 

 sections of different fronds, X 4 '■> g> transverse section much enlarged to show rhom- 

 boidal sections of branches, with dissepiment connecting them, the thin expanding car- 

 inae connected by scalae. (After Hall.) 



Branches straight, parallel and rigid, the carinse and scalae mak- 

 ing a ladder-like structure, the carinae projecting above the very 

 oblique scalae. 



Hamilton of New York and Ontario. 



