XXII 



SYNOPSIS OF GENERA. 



Semiopora, Hall (Trans. Albany institute, vol. x, p. 193. 1881). 

 [Type, Semiopora bistigniata, Hall.] 



Zoariuui ramose, flattened, growing from a spreading base. Branches cellu- 

 liferous on both sides ; cells arising from a mesotheca. Apertui-es separated 

 longitudinally by two minute pits or mesopores. 



Example: Semiopora bistigmata, pi. l.\ii, figs. 27-29. 



Intrapora, Hall (Trans. Albany Institute, p. 157. 1881). 



[Type, Intrajjora put«olata. Hall.) 



Zoarlum as in Stictopora. Interapertural space occupied by minute angular 

 pit*. Intercellular structure irregularly vesiculose. 



Example: Intrapora puteolata, pi. xxix, figs. 18-26. 



Thamniscus, King (An. Mag. Nat. Hist., 2d ser., vol. iii, p. 389. 1849). 

 [Type, Ceratophytes dubius, Schlotheim.] 

 Zoarium ramose, growing in fl.attened or infundibuliform fronds. Branches 

 frcijuently bifurcating, not ansistomosing or connected by dissepiments, cellu- 

 liferous on one side. Cells tubular. Apertures circular or oval, sometimes 

 polygonal 



Examples: Thamniscus variolata, pi. xxii, figs. 34—46. 

 Thamniscus muUiramus, pi. xxxiii, figs. 1-5. 



Fenestella, Lonsdale (Murchison's Silurian System, p. 677. 1839). 

 [Type, Gorgonia antiqua, Goldfuss.] 

 Bryozoum ramose, forming Habellate or infundibuliform fronds, composed of 

 slender branches celluliferous on one side, connected by transverse processes 

 or dissepiments. Cell apertures in two ranges, separated by a carina or line 

 of nodes. 



Examples: Fenestella Sylvia, pi. xx, figs. 4-7. 



Fenestella variapora, pi. xlv, figs. 1-13; pi. xxxv, fig. 17. 



Fenestrapora, s. o., Hall (Report of State Geologist for 1884, p. 36. 1885). 

 [Type, Fenestrapora biperforata. Hall.] 



Bryozoum infundibuliform, branches connected by dissepiments. Cell aper- 

 tures in two ranges, separated by a carina bearing pores. Non-celluliferous 

 face with conspicuous pores. 



Example : Fenestrapora biperforata, pi. Ixvi, figs. 34-39. 



