Descriptions of Families and Genera. 



Family Fenestellidae, King. 



All the members of this family are reticulate, funnel or fan 

 shaped, and are composed of slightly diverging bifurcating 

 branches, either rigid and connected by cross- bars (dissepiments) 

 which are formed by opposite projections from adjacent 

 branches, uniting midway between the branches, or sinuous 

 and connected at intervals by anastomosis; in both cases the 

 frond being perforated by symmetrically disposed quadrate or 

 oval spaces (fenestrules). The cells are short utricular and 

 arranged in two or more series, on one side of the branch only. 

 The cell apertures are usually circular, surrounded by an eleva- 

 tion (peristome). The noncelluliferous face of the frond is com- 

 posed of a more or less thick stratum of calcareous fibrous tissue, 

 which is perforated by minute tubuli, rectangularly to the surface, 

 and in some forms by larger thick walled tubes, the use of which 

 is not known. The surface is usually striated and ornamented by 

 granules, nodes or spinules. These features in aged fronds are 

 usually obscured or obliterated by a calcareous deposit ; the dif- 

 ference in appearance between the older and more recent por- 

 tions of the frond being very marked. 



The following genera are included in this family: Anastomo- 

 POEA, Archimedes, Akchimedipora, Cyclopobi!^a, Fenestella 

 and its groups, Fenestralia, Fenestrapora, Flabeliiporina, 

 Heliuopora, Hemitrypa, Isotrypa, LocuLiPORA, Lyropora, Lyro- 

 poRiDRA, Lyroporina, Lyroporella, Phyllopora, Polypoba, Poly- 



FORELLA, PtILOPORA, PtILOPORELLA, PtILOPORINA, PiNNAPORELIA, 

 PiNNAPORINA, PeTEPORILLA, PeTEPORINA, SyNOCLADIA, SeMICOS- 



ciNiuM, Tectulipora, Tectuliporella and Unitrypa. 



Several of these genera have been placed by authors under 

 other families or subfamilies but they are so intimateh^ connected 

 and the change from one form to another, through intermediate 

 forms, is so gradual (as shown in the article on the "Genera of 

 Fenestellidge " in the Annual Report of the State Geologist for 

 1893) that a separation into different families does not seem ad- 



