"«be. ] CANADIAN PALAEOZOIC CORALS. 167 



this species and approach in size those of the smaller forms of P. Billingsi. 

 Measurements taken from the two last mentioned specimens give the fol- 

 lowing results : — Diameter of calyces from 17 to 20 mm., diameter of 

 central pits 6 to 7 mm. In all three specimens the septa number from 

 about forty to forty -four, and the pore-openings can be detected in natural 

 transverse sections. 



" Dr. Whiteaves records* the occurrence of this species in the Hamil- 

 ton formation on the authority of Mr. Schuchert, who collected a good 

 specimen of it at Bartlett's Mills in 1895/' (Lambe, 1899.) 



Phillipsastr,ea Verrilli, Meek. (Sp.) 

 Plate XIV., figs. 5, 5a, 56 and 6. 



Smithia Verrilli, Meek. 1868. Trans. Chicago Acad, of Sciences, vol. I., p. 83, pi. XL, 



figs. 7, la, 76. 

 Phillipsastrcea Hennahi, Whiteaves. 1891. Contr. to Can. Palseon., vol. I., pt. III., 

 p. 204. 



Corallum compound, forming irregular, depressed subhemispherical 

 masses, commonly convex above and obtusely pointed below, but some- 

 what varied in shape and subspherical when young ; composed of con- 

 fluent corallites, from 5 to 10 mm. in diameter, that terminate above in 

 calyces that have a central pit surrounded by a raised circular rim, 

 averaging about 3 mm. in width and 1 or 2 mm. high, outside of 

 which is a flat sunken margin striated by radiating septal ridges of equal 

 size. Increase by marginal calicinal gemmation. Covered below by a 

 concentrically wrinkled epitheca. Surface of attachment small. Septa 

 generally confluent with those of neighbouring corallites, carinated on 

 their sides, thickened near the centre of the corallite so as to form a 

 pseudowall that appears at the surface as the raised rim surrounding the 

 central pit, numbering from twenty to nearly forty, of two alternating 

 sizes, the secondaries scarcely projecting past the inner wall beyond which 

 the primaries are attenuated and continued to the centre, where they are 

 generally twisted. Tabulae usually well developed, flat, filling the area 

 inside the inner wall and cut into by the primary septa, twelve or four- 

 teen occurring in a space of 5 mm. Dissepiments rather small, convex, 

 occupying the interseptal spaces in the marginal area and arching slightly 

 upward toward the tabulae. The raised mural rings of the surface show 

 in well preserved specimens a considerable variation in their amount of 

 protrusion, but in worn specimens the general appearance of the surface 

 resembles that of the type specimen as figured (op. cit.) The septal 

 ridges, although of equal size in the marginal area, become slightly 



* Geol. Surv. Canada, Contr. Canad. Palseont., vol. I., pt. V., p. 365. 



