iambe.] CANADIAN PALEOZOIC CORALS. 39 



about 5 mm. in diameter when in contact, and the constrictions are much 

 more pronounced and very variable in their distance apart, causing the coral- 

 lites to appear as slender cylindrical tubes from 2 to 5 mm. in diameter, with 

 abrupt thin horizontal expansions at intervals of from 1 to over 10 mm. 

 apart ; the spaces separating the cylindrical portions of the corallites are 

 here seen to be frequently much wider than the diameter of the corallites 

 themselves. Between these extremes intermediate gradations occur in 

 the same or in different specimens. The expansions in some specimens 

 occur somewhat in the same plane, forming a floor in which the polygonal 

 outlines of the corallites are seen in juxtaposition. The interior of the 

 corallites is obscurely marked by from about thirty to fifty longitudinal 

 striae. Pores unequal in size, sometimes over -5 mm. in diameter, gene- 

 rally in one or two horizontal rows, where the corallites are in contact. 

 Septal spines represented by close set, longitudinal, often interrupted 

 rows of stout sharply pointed tubercles, generally more clearly defined on 

 the contracted parts of the corallites than elsewhere. Tabulae numerous, 

 and of the same nature as those of M. convexa. The exterior surface of 

 the corallites is marked by fine encircling rings of growth and by longi- 

 tudinal lines corresponding to the inner striations. In a part of one 

 specimen in particular the corallites, which are elsewhere normal in 

 structure, approach closely in structure those of M. convexa in that they 

 are constricted only at rather lengthy intervals, leaving the corallites 

 polygonal and in contact for some distance. 



Occurs in the Corniferous limestone of Ontario, near Woodstock, and 

 in the townships of Walpole and Cayuga. 



Michelinia favositoidea, Billings, em. (favosoidea). 



Michelinia favosoidea, Billings. 1S59. Canadian Journal, new series, vol. IV., p. 114. 

 Michelinia favositoidea, Ilommger. 1876. Geol. Sur. Mich., Foss. Corals, p. 73, p. 

 XXVII., fig. 4. 



" Corallum forming large hemispheric or flattened masses ; cells un- 

 equal in size, adult diameter about two lines and a half ; diaphragms 

 flat, horizontal, with small vesicular swellings, usually around the 

 margins of the upper surface ; septal striae very obscure, six to eight on 

 each plane side of the cells ; pores very small, irregularly distributed, 

 sometimes in rows of five or six across the cell, about one-sixth of a line 

 distant from each other in some places, and sometimes absent in spaces 

 of half a line in width." (Billings). In the type specimen small, stout, 

 short septal spines occur in abundance on the inner surfaces of the walls 

 of the corallites. 



Found in the Corniferous limestone at Port Colborne, Ont. 



