lamm.] CANADIAN PALAEOZOIC CORALS. 31 



sides. Mural pores of average size, irregularly dispersed. Tabulae com- 

 plete, apparently numerous. Rominger mentions the presence in his 

 specimens*, in the interior of the corallites, of three "crests" such as are 

 found in Cladopora cryptodens, Billings, one on the inner side of the wall 

 near the mouth, the other two opposite on the outer wall. The epitheca 

 covering the lower surface and mentioned by Rominger in his description 

 of the species is not preserved in the Canadian specimens. 



This species is very like the Devonian form Cladopora turgida, Romin- 

 ger in general appearance and structure, and apparently differs only from 

 it in its less robust growth and in its usually incrusting habit. 



Niagara formation. — North end of Lake Temiscaming, Que., R. 

 Bell, 1887 ; Isle of Mann (Burnt Island) Lake Temiscaming, A. E. 

 Barlow, 1893. 



Cladopora cryptodens, Billings. (Sp.) 



(Plate I., figs. 5, 5a.) 



Alveolites cryptodens, Billings. 1859. Canadian Journal, new series, vol. IV., p. 115, 



fig. 16. 

 Favosites polymorpha {pars), Billings. 1859. Ibid, p. Ill, fig. 11. 

 Striatopora formosa, Billings. 1860, Canadian Journal, new series, vol. V., p. 254. 

 Cladopora magna, Hall and Whitfield. 1873. Twenty- third Report, N.Y. State 



Museum of Nat. Hist., p. 230, pi. 10. figs. 3 and 4. 

 Cladopora cryptodens, Rominger. 1876. Geol. Sur. Mich., Foss. Corals, p. 49, pi. 



XX., figs. 1 and 2. 

 Pachypora or Alveolites (cfr. A. cryptodens, Bill.), Whiteaves. 1892. Contr. to Can. 

 Palseon., vol. I., pt. IV., p. 273. 



Corallum ramose, rather straggling in its growth, consisting of slender 

 stems, circular in transverse section, sometimes as much as 15 mm. in 

 diameter, that branch or bifurcate at rather distant intervals. Corallites 

 radiating upward and outward, and issuing obliquely to the surface in 

 slightly expanded somewhat circular calyces margined below by a sharp 

 prominent well defined lip. Walls of the corallites moderately thin at 

 first, but becoming thicker as the surface is approached, where the maxi- 

 mum thickness is attained. Corallites circular or rounded polygonal in 

 section, gradually increasing in size until an average diameter of 1 *5 mm. 

 is attained at the surface. Tabulae, as seen in longitudinal section, 

 complete, about" "5 ram. apart. Squamulse small, occurring on the sides 

 of the walls of the corallites. Pores rather irregular in distribution, of 

 moderate size. Three longitudinal ridges are present in the interior of the 

 corallites ; beginning near the mouth they appear to extend a short dis- 

 tance inward and are apparently denticulated at the edge ; one of these 



* From the Niagara limestone of Point Detour, Drummond Island, Lake Huron, &c. 



