38 AMERICAN FOSSIL BRYOZOA. [bull. 173. 



Genotype: Gorgonia a^itiqua (Goldiuss'i) Lonsdale. Accepted geno- 

 type: FeneHtella plehela McCoy. Range, Ordovician-Cavboniferous. 

 One hundred and eleven described and a considerable number of new 

 species. 



Semicoscinium Prout (Cryptopora Nicholson, Carinopora Nicholson, 



Cycloporina Simpson). 



Zoarium funnel shaped, celluliferous on the outer side; dissepiments 

 wide, very short, the branches appearing to anastomose on the non- 

 poriferous face, where the fenestrules are subrhomboidal or rounded; 

 apertures in two rows, median keel very high and expanded at the 

 summit. 



Genotype: Semicoscinium, 7'homhoideurn,'Pvo\xi. Silurian, Devonian. 

 Twenty-six species. 



Fenestrapora Hall. 



Zoarium as in Semicoscinium, except that the reverse of the zoarium 

 and the expanded summits of the carinas bear large scattered pores or 

 pits. 



Genotype: Fenestraporahiperforata^'AW. Devonian. Three species. 



Isotrypa Hall (Tectuliporella Simpson). 



Zoarium funnel-shaped, branches connected by dissepiments; aper- 

 tures in two rows, separated by a carina; the carina? prominent, 

 expanded at the summit; summits connected by round or oval lateral 

 bars, usualW situated above the dissepiments; on the reverse face a 

 more or less conspicuous pore occurs on or near each dissepiment. 

 The superstructure gives the obverse much the appearance of the j 

 reverse of the zoarivim. 



Genotype: Fensstella {Isotrypa) conjunctiva Hall. Devonian. Two 

 species. 



LocuLiPORA Hall (emend.) (Tectulipora Hall). 



Zoarium funnel-shaped, branches connected by short, typically 

 reduced to a minimum, nonporiferous dissepiments; apertures in two 

 rows; branches and dissepiments carinated, the carina coalescing; 

 summits of carina much expanded, angular, and slightly carinated, 

 their width usualh^ equaling that of the branches and dissepiments 

 below and hence causing difficulty in distinguishing the obverse and 

 reverse sides. 



Genotype: Fenestella perforata Hall. Silurian, Devonian. Four 

 species. 



Unitrypa Hall. 



Zoarium funnel-shaped; branches connected by dissepiments; aper- 

 tures in two rows, separated by a carina; carina prominent, thickened 



