No. 1797. NEW TUBULIPOROID BRY0Z0A—BAS8LEB. 527 



dissimilis. C. tennesseensis , with its exsert aperture and transversely 

 rounded zooecia, is probably an early expression of the Silurian C. 

 dissimilis. 



The dimensions for C. canadensis are as follows : Average length of 

 zoarium, 0.80 mm.; width at constricted proximal portion, 0.22 mm.; 

 diameter at most expanded part, 0.37 mm.; diameter of aperture, 

 0.20 mm. 



Occurrence. — Middle Ordovician, Swampy Island, Lake Winnipeg, 

 Canada. 



