lambe. ] CAANDIAN PALEOZOIC CORALS. 29 



Ccenites Selwynii bears a close resemblance to the Silurian C. linearis, 

 Milne-Edwards and Haime*, but its calyces are about twice as broad 

 and are more generally curved than straight. 



Rare in the Corniferous limestone of Ontario ; the specimen described 

 by Nicholson, the only one that he had seen, was collected at Port Colborne; 

 the single specimen representing the species in the collection of the Geolo- 

 gicol Survey was obtained by Mr. S. W. Howard, at Hagersville, Ont., and 

 presented to the museum in 1890. 



Genus Cladopora, Hall. 1852. 



(Palaeon. New York, vol. II., p. 137.) 



Corallum ramose, sometimes reticulated, flabellate or palmate, or forming 

 laminar expansions, composed of closely united, subpolygonal corallites 

 with expanded calyces that are oblique to the surface and margined below 

 by a lip ; walls of the corallites at first thin but becoming gradually thicker 

 as the surface is approached ; pores not numerous, dispersed ; tabular com- 

 plete, transverse ; three denticulated ridges developed near the calyces ; 

 squamulse sometimes present ; opercula closing the calyces present in some 

 species ; epitheca rarely developed. 



This genus is distinguished from Favosites and Alveolites principally by 

 the gradual thickening of the walls of the corallites near the surface, and 

 by the expansion'of the calyces, which are bordered below by a more or 

 less prominent lip. The corallites are at first subpolygonal and sometimes 

 slightly compressed, later becoming more nearly circular as the walls 

 thicken ; in the ramose or fan-shaped forms they diverge from an inner 

 axial line or plane and end in circular, oval, reniform, sometimes almost 

 lunate calyces more or less oblique to the surface. The longitudinal ridges 

 apparently do not extend far into the corallites and end where the calycular 

 expansion takes place. The walls of the corallites are distinct and do not 

 completely coalesce. 



Cladopora multipora, Hall. 



Cladopora multipora, Hall. 1852. Palaeon. New York, vol. II., p. 145, pi. XXXIX. 



figs. 1 a—g. 

 Favosites ? multipora, Nicholson. 1875. Palseon. of Ontario, p. 53. 



" Frond ramose or reticulate ; branches short, terete, in the reticula- 

 tions cylindrical ; cells numerous, closely arranged, penetrating to the 

 axis in a slightly oblique direction ; openings upon the surface sub- 

 angular or circular, sometimes apparently tranverse ; reticulations irregu- 



Brit. Fossil Corals, pi. LXV. fig. 3. 



