142 NOTES ON THE FOSSILS OF ONTARIO. 



the mouths of the cells, which ai-e quincixncially arranged. The cell 

 mouths are strongly elevated above the surface, and have the form of 

 rounded pustules, perforated centrally by a minute circular aperture 

 surrounded by a thickened lip. About five cells occupy the space of 

 one line, and they are separated from one another by about their own 

 diameter. 



Locality and Formation. — Abundant in the Clinton Group at 

 Dundas. 



14. Ph^nopora ensiformis, Hall. {Ref. Pal. N.Y., Vol. II., 

 pi. xviii., figs. 8a.-c.) Polyzoary forming a thin flattened expan- 

 sion of an ensiform shape, curved and tapering towards the base, and 

 varying in leng-th from half an inch to one inch. Cells arranged in 

 longitudinal rows, separated by elevated longitudinal thread-like 

 lines, the number of rows increasing as we proceed from the base 

 towards the proximal end. Apertures of the cells oval or oblong, 

 alternating in contiguous rows, about seven in the space of one line 

 measured longitudinally. No striated and non-celluliferous marginal 

 zones appear to exist ; but none of our specimens exhibit the internal 

 structure ; and we are therefore uncertain whether the species should 

 not really be referred to Ptiloclictya. 



Locality and Formation. — Common, though usually fragmentary, in 

 the Clii^ton Group at Dundas. 



15. Ptilodictya crassa. Hall. {Ref. Stictopora crassa, Hall, Pal. 

 N.Y., Vol. II., pi. xviii., figs. 4a-c.) Polyzoary composed of 

 linear flattened expansions which branch dichotomously at short 

 intervals, and have a width of from a line to a line and a half. Cell 

 mouths long-oval, arranged in longitudinal rows, about five in a line 

 measured vertically, and seven or eight in the same space measured 

 transversely. According to Hall, the margin of each cell-aperture 

 is surrounded by a shallow groove, which gives the surface a striated 

 appearance ; but this feature has not been observed by us. The mar- 

 .gins do not appear to exhibit a distinct striated and non-celluliferous 

 border ; and as the internal structure is still unknown, there is some 

 doubt if the species is truly referable to Ptilodictya. 



Locality and Formation. — Clinton Group, Dundas. 



16. Ptilodictya (I) raripora, Hall. (lief. Stictopora raripora, Hall, 

 Pal. N.Y., pi. xviii., figs. 5a— c.) Polyzoary composed of small 

 «ub -cylindrical branching stems, about half a line in diameter. Cells 



