38 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



Corallum when young of a disk-like form with a convex upper surface 

 and almost flat below, becoming later of a more hemispherical shape and 

 passing with age into a roughly upright cylindrical mass without much 

 lateral expansion ; attaining a height of 10 or 11 inches with a breadth 

 of 4 or 5. The point of attachment of the corallum is at the centre of 

 the base which is covered by a strong, concentrically wrinkled epitheca. 

 Corallites large, polygonal, thin walled, attaining a diameter of 9 or 10 

 mm., with small ones interspaced among the large ones ; in some specimens 

 the average size of the mature corallites is much less. Tabulae strongly 

 convex, numerous, with many secondary tabulae or cysts resting on the 

 complete tabulae, principally nearer the walls of the corallites than at the 

 centre, the whole forming a vesiculose mass filling the interior of the coral- 

 lites. The presence of the secondary tabulae on the primary ones gives 

 to the latter a peculiar blistered appearance when seen from above. In 

 corallites of average size about forty parallel, longitudinal striae occur on 

 the inner surface of the walls, which are further decorated on the spaces 

 between the striae by numerous short blunt septal spines. Pores of rather 

 unequal size, edged with a raised rim, generally irregularly distributed 

 though sometimes becoming more numerous and forming regular vertical 

 rows between the longitudinal striae. 



Occurs in the Corniferous limestone of Ontario at Port Colborne, 

 Cayuga and near Woodstock. 



Michelinia Clappii, Milne-Edwards andHaime. (Sp.) 



Chonostegites Clappi, Milne-Edwards and Haime. 1851. Polyp. Foss. desTerr. Palaeoz., 



p. 299, pi. XIV., figs. 4, 4a. 

 Miehelinia intermittens, Billings. 1859. Canadian Journal, new series, vol. IV., p. 113. 

 Hairneophyllum ordinatwm, Billings. 1859. Canadian Journal, new series, vol. IV., p. 



139, fig. 29. 

 Michelinia Clappii, Rominger. 1876. Geol. Sur. Mich., Foss. Corals, p. 75, pi. 

 XXVIII., figs. 3 and 4. 



Corallum forming large, somewhat hemispherical or lenticular masses, 

 broadly convex above and rather flat or convex below, with subparallel 

 corallites diverging outward and upward from a central basal point ; 

 reaching a breadth of over 1 foot and sometimes about 8 inches 

 high. The corallites are thin walled, constricted at varying intervals, 

 polygonal when in contact, circular and separated by a space from each 

 other where constricted. In some specimens the corallites are large, 

 nearly 8 mm. in average diameter, and slightly but sharply contracted 

 at intervals of from 1 to 4 mm., the average width of the corallites where 

 constricted being a little over 5 mm. ; as seen from above the corallites 

 appear circular. In other specimens the corallites are smaller, averaging 



