96 CONTRIBUTIONS TO CANADIAN PALiEONTOLOGY. 



In the above mentioned specimen from Pointe Claire, the corallites 

 show the usual four septa extending toward the centre, but at times also 

 secondary ones proceeding from the main wall one to each space between 

 the primary septa and the angles of the tube wall. A corallite in which 

 these secondary septa are developed suggests a stage of growth prepar- 

 atory to its division into four smaller ones, and strengthens the idea that 

 the manner of increase of the corallum was by fission of the old tubes. 

 When by the union of the primary septa young corallites were formed, 

 the secondary septa became in turn primary ones in the new corallites, in 

 which septa were probably also developed on the newly completed septal- 

 walls. At a certain stage of growth it is thus seen that a corallite may 

 have as many as twelve septa, four of them being primary and eight 

 secondary. 



April, 1897. 



