BRVOZOA. 227 



On celluliferous side the branches are rounded, of uniform size near base of frond 

 and enlarging gradually, reaching maximum width just before a bifurcation, rarely 

 sinuous or anastomosing, bifurcation occurs regularly usually at intervals of 20 mm., 

 width of branches just before a bifurcation .60 mm. Dissepiments strongly developed. 

 Fenestrules elongate oval, width .45 mm., length approximately three times as great. 

 Cell apertures in from two to four ranges, rarely five, 20 in the space of 5 mm. Shape 

 not distinctly determined. 



Remarks — -This form has a greater number of apertures than Polypora hexagonalis 

 Hall, and the dissepiments are not so distinctly carinated as in that species. 



Horizon — Upper beds. 



Figured specimen No. 27660 Walker Museum. 



Polypora media sp. nov. 

 Plate 60, figure 3 



Description — Zoarium infundibuliform, size unknown. Branches of medium 

 strength on the obverse side, sinuous, rounded, sometimes slightly flattened, equal to 

 about half the width of the interstices. Dissepiments about equalling the branches in 

 strength, or slightly narrower, width from .60 to .70 mm., 4 in the space of 5 mm., 

 flat to slightly rounded, on a plane with the branches. Surface granular. ^ Fenestrules 

 elliptical in outline, length usually about 1 mm., width from .50 to .60 mm. 



On the celluliferous side the branches are less sinuous than on the reverse, gradu- 

 ally increasing in width from .40 to .80 mm. just before a bifurcation, 16 to 17 occupy 

 the space of 1 cm. Dissepiments about the same strength as branches. Zooecial aper- 

 tures in 2 to 4 ranges, 17 to 18 in 5 mm., separated by half the diameter of an aperture, 

 sub-circular in outline, margins distinct. 



Remarks — This species differs from Polypora hexagonalis Hall in having the aper- 

 tures more widely disposed, in having a granular -surface on the reverse side, and in 

 showing no carinated dissepiments. 



Horizon — Upper beds. 



Holotype No 27659 Walker Museum. 



Polypora valida sp. nov. 

 Plate 60, figures 4, 5 



Description — Zoarium apparently infundibuliform, size unknown. Branches strong, 

 straight, rounded slightly or sometimes almost flat, width above a bifurcation .50 mm., 

 increasing to 1 mm. below a bifurcation. Dissepiments about one-half width of branches, 

 on same plane as latter or a little depressed on the reverse side, 3 in the space of 5 mm. 

 Fenestrules sub-triangular to oval, width .75 mm., length about twice as great, 6 occupy 

 the space of 1 cm. 



On the celluliferous side the fenestrules are elongate oval. Branches strong, 6 to 

 7 in 1 cm. Cell apertures in 4 to 5 ranges just below a bifurcation, and from 2 to 3 just 

 above bifurcation, 20 present in 5 mm., circular to slightly oblong in outline, separated 

 by less than half the width of an aperture. Both branches and dissepiments are covered 

 with nodes, these being arranged regularly in parallel bands. 



Remarks — This species may be differentiated from Polypora hexagonalis Hall, by 

 the less sinuous branches, and by the greater number of branches. From the other asso- 

 ciated species of this geological horizon it differs in having stronger branches, and in the 

 presence of numerous nodes on the celluliferous side. 



Horizon — Upper beds. 



Holotype No. 27658 Walker Museum. 



