52 AMEBIC AN FOSSIL BEYOZOA. [bull. 173. 



cavities; or a unilaminate base on which the ridges are greatly devel- 

 oped and form large leaves; these ridges or leaves are composed of 

 two layers of zooecia growing in opposite directions from a mesotheca; 

 in the angles of each cup is a depressed noncellulif erous furrow which 

 with similar furrows in neighboring cups produces a thin junction 

 between the leaves; surface of the ridges and of the cups with elon- 

 gated solid maculae or "dimples;" structure otherwise as given for the 

 family. 



Genotype: Coscinium. plumosumTrout. Mississippian. Eight spe- 

 cies. 



Phractopora Hall. 



Like Glyptopora except that the apertures are relatively more 

 rounded and larger, and the junction angles are celluliferous and thicker 

 than any other part of the leaves. 



Genotype: Phractojpora cristata Hall. Devonian, Mississippian. 

 Four species. 



Ceramella Hall. 



Zoarium consisting of thin, foliaceous expansions, arising from a spreading base; 

 celluliferous on each face; cells tubular, oblique; cell apertures oval or circular, dis- 

 posed in quincunx order; surface marked by sterile maculae, which are usually 

 depressed below the general surface of the branch.^ 



Genotype and only known species: CerameUa scidacea Hall. De- 

 vonian. 



EvACTiNOPORA Meek and Worthen. 



Zoarium free, consisting of four or more vertical leaves, arranged 

 in a cruciform or stellate manner; rays free in the upper half, united, 

 thick, and nonporif erous in the basal portion; apertures on both faces 

 of the leaves or rays, subcircular; interspaces solid at the surface, 

 occupied by vesicular tissue internally. 



Genot3^pe : Eixictinopora radiata Meek and Worthen. Mississippian. 

 Four species. 



GoNiocLADiA Etheridge, Jun. (Carinella Etheridge, Jun.). 



Family ACTINOTRYPID^ Ulrich 



AcTiNOTRYPA Ulrich. 



Zoarium a thin bifoliate expansion; apertures show the projecting 

 ends of from eight to ten vertical septa-like ridges that extend down 

 along the sides of the vestibule nearly or quite to the orifice. 



Genotype and only known species: Fistulipora peculiaris Rominger. 

 Mississippian. 



1 Simpson, Fourteenth Ann. Rep. State Geologist New York for the year 1894, p. 527. 



