NicKLEs ANP BAssLER.] DIAGNOSES OF GENERA. 25 



cles and of zooecia slig-htl}' larger than the average; hmarium generalh' 

 well developed, sometimes wanting; zo(Bcial tubes cylindi'ical or some- 

 what compressed, thin-walled, with diaphragms; walls minutely porous; 

 apertures usually direct, closed at times b}' perforated covers; vesic- 

 ular tissue occupies the interzooecial space. 



FiSTULirouA McCoy (Lichenalia Hall, in part, DiDYMoroRA Ulrich, 

 Dybowskia and Dybowskiella Waagen and Wentzel, Fistuijpo- 

 RELLA Simpson). 



Zoarium massive, lamellate, ramose, parasitic or free ; under surface 

 with a ^vrinkled epitheca; zocecia cylindrical or somewhat compressed, 

 direct or almost so, thin-walled until near the surface, and provided 

 usually with a few diaphragms, and encircled by one or more series of 

 vesicles; apertures subradially arranged about the macula?, ovoid, sub- 

 triangular or pyriform, the lunarium more or less strongh^ developed; 

 surface between apertures smooth or granular. 



Genotype: Fisti(li/p(jra7ninor McCoy = Oalamopora incnistans Phi\- 

 lips. Range, Silurian-Carboniferous. Sixty -two described and a 

 considerable number of new species. 



Cyclotrypa Ulrich. 



Like Fistulipora, but the lunarium obsolete and the zooecial tubes 

 circular in cross section. 



Genotype: J^istulijxmi C077iniums IJlrich. Devonian. Two species. 

 Future work may disclose new species and show that species now 

 referred elsewhere belong here. 



Eridopora Ulrich (Pileotrypa Hall). 



Zoarium a thin, parasitic sheet; apertures oblique, subtriangular or 

 ovoid; lunarium very prominent, overarching. 



Genotype: £ridopo7'amacrostoma\J\v'ich. Devonian, Mississippian. 

 Four species described and several awaiting description. 



Hexagonella Waagen and Wentzel. 



Zoarium as in Fistulipora, but the surface is marked off into gener- 

 all}" hexagonal spaces, which are divided from each other by more or 

 less elevated ridges, and usually have a macula in the center of the 

 inclosed space. 



Genotype: Hexagonella ramosa Waagen and Wentzel. From the 

 Carboniferous of India. Two undescribed species from the Hamilton 

 and Warsaw. 



Pin acotrypa Ulrich (FisTULiPORiNA Simpson, Fistulicella Simpson). 



Zoarium usually a thin contorted expansion, with a wrinkled epitheca 

 on the basal surface; zocecia thin-walled, with a few diaphragms; 



