250 The Ottawa Naturalist. [March 



other times interfered with by the septal ends which cut into 

 them and destroy their horizontal continuity giving them more 

 the character of dissepiments than of tabuhie. Dissepiments 

 filling the interseptal spaces and curving upward and outward 

 in regular order, those in the peripheral region being gener- 

 ally larger than those nearer the centre ; they are pierced at 

 their junction with each other by oval or circular pore-openings 

 forming a uniserial row midway between the septa. 



Locality and formation. — Corniferous formation of Ontario. 



Phillif'Sa.str^.a Verneuili, Milne-Edwards and Haime. 



Phillipsastrea Verneuili, Milne-Edwards and Haime. 185 1. 

 Polyp. Foss. Terr. Palaioz., p. 447, pi. 10, fig. 5 



" Verneuili, Billings. 1859. Canad. Journ., vol. IV, 



new series, p. 127, fig. 24. 



Phillipsastrcza Verneuili, Rominger. 1876. Geol. Surv. Michigan, 

 Fossil Corals, p. 127, pi. xxxvill, fig. 2. 



Phillipsastrea affinis, Billings. 1874 Geol. Surv. Canada, Palaeoz. 

 Fossils, vol. II, pt. I, p. II. 



Phillipsastrea Verneuili, Nicholson. 1875. Rep. Palasont. Prov. 

 Ontario, p. 78. 



Corallum forming large discoidal masses over 30 cent, broad 

 and 8 cent, thick or high, upper surface flat, lower surface irreg- 

 ular, strongly marked by concentric foldings or wrinkles of 

 growth and covered by an epitheca. Septa numbering from 

 about thirty to forty-six Corallites varying in diameter from 

 10 to 16 mm. Central pit of the calices from 3 to 5 mm. 

 in diameter. In no particular does this species differ from P. 

 Billingsi except in the smaller size of its corallites and in a 

 diminution in the number of the septa. In transverse sections 

 and in weathered specimens it is observed that a single row of 

 pore-openings occurs between each pair of septa, the pores 

 piercing the dissepiments where they rest on each other, the 

 distance apart of the pores in a single row thus depending 

 on the size of the dissepiments. This pore structure which 



