BRYOZOA. 613 



but on the obverse its branches are more distinct and occa- 

 sionally separated by a narrow non-celluliferous strip. Several 

 species of this type occur in the Hamilton group of New York 

 and Canada. It is not easy to decide whether they had better 

 go with Phyllopora or Polypora. 



PHYLLOPOKA ASPERA Ulrich. 



PI. XLTV. figs. o-ob. 



Zoarium infundibuliform, celluliferous on the outer side, con- 

 sisting of anastomosing branches, forming a regular round 

 meshed net-work. Branches rather strongly convex, from 0.4 

 to 0.6 mm. wide. Fenestrules broad oval or circular, 0.2 or 0.3 

 mm. in diameter, smallest near the base, arranged in sub-regu- 

 lar longitudinal and diagonally intersecting series, with five 

 lengthwise and six diagonally in 5 mm. Zooecia in two or three, 

 usually alternating ranges. Apertures circular, about 0.13 mm. 

 in diameter, so far as observed, without a peristome, their di- 

 ameter or less apart, rather irregularly arranged, thirteen or 

 fourteen in 3 mm. Distributed over the surface among the 

 apertures are a variable number of strong blunt spines, giving 

 this face of the zoarium the rough aspect that suggested the 

 name. On the reverse the fenestrules are nearly or quite as 

 wide as the branches. Surface of the latter smooth or minutely 

 granulose. 



The small size of the zoarium and fenestrules, and the ar- 

 rangement of the zooecia in only two or three rows on a branch, 

 distinguish this species from all others of the genus, save one, 

 known to me. The arrangement of the zooecia is very much 

 as in P. ehrenbergi. 



Position and locality: Upper Helderberg group. Rare at the 

 Falls of the Ohio. 



PHYLLOPORA SUPERB A Ulrich. 



PI. XLIV, figs. 6-6c, and PI. LV, figs. 9, 9a. 



Zoarium a reticulated flabellate expansion, known to attain a 

 height and width of between 4 and 5 cms. 



