SYNOPSIS OF GENERA. 



XV 



Tropidopora, Hall (Report of State Geologist for 1886, advance sheets. 

 Expl. pi. 25. 1886). [Type, Tropidopora nana, Hall.J 



Zoarium ramose, solid. Cell apertures arranged in irregular longitudinal 

 rows, separated by sinuous ridges. Interior structure unknown. 



Example : Tropidopora nana, pi. xxv, figs. 25, 26. 



Diamesopora, Hall (Pal. N. Y., vol. ii, p. 158. 1852). 

 [Type, Diamesopora dicliotoma. Hall.] 

 Zoarium ramo.se, hollow, lined with an epitheca. Peristomes strongly ele- 

 vated on the posterior margin. Intercellular space solid. 



Examples: Diamesopora constrida, pi. x, figs. 14-19 ; pi. xxiiiA, fig. 7. 

 Diamesopora camerata, pi. xxvi, figs. 9, 10. 



Acanthoclema, Hall (Report of State Geologist for 1886, advance sheets. 

 Expl. pi. 25. 1886). [Type, Trematopora alternata, Hall.] 

 Zoarium ramo.se, solid. Cells arising from a filiform axis; apertures arranged 

 in longitudinal rows sep.arated by ridges. Usually with one or two nodes lon- 

 gitudinally between the cells, which are represented in the interior by short tubuli. 

 Examples : Acanthoclema alternatum, pi. xxv, figs. 8-10. 



Acanthoclema scutulatum, pi. Iv, figs. 15-17; pi. Ivi, figs. 19, 20. 



Bactropora, n. n. [Type, Trematopora ? granistriata. Hall.] 



Zoarium with distant, bifurcations, solid. Base tapering, acute at the apex, 

 striated. Cells tubular, arising from the center of the branch, septate. Aper- 

 tures arranged in longitudinal rows. 



Examples : Bactropora granistriata, pi. Ixvi, figs. 20-22. 

 Bactropora curvata, pi. Ixvi, figs. 14-16. 



Nemataxis, Hall (Report of State Geologist for 1886, advance sheets. Expl. 

 pi. 25. 1886). [Type, Nemataxis fibrosus, Hall.] 

 Zoarium ramose, .solid. Cells arising from a filiform axis, in contact for the 

 greater portion of their length, but separated by a fibrous tissue near the surface. 

 Apertures arranged in longitudinal rows, separated by ridges. 

 Examples: Nemataxis fibrosus, pi. xxv, figs. 30-36. 

 Nemataxis simplex, pi. Ixvi, figs. 17-19. 



Callopora, Hall (Pal. N. Y., vol. ii, p. 144. 1852). 



[Type, Callopora elegantula, Hall.] 

 Zoarium ramose solid. Cells cylindrical, septate. Apertures circular or oval, 

 often closed by a perforate operculum, marked by radiating ridges. Meso- 



