SLOCUM. — FINITE CONTINUOUS GROUPS. 109 



A = 



and this vanishes if the a's satisfy the condition a^i + «"2 + a% = 4 ^^ tt^, 

 where ^' is an arbitrary integer. The adjoined of this group is 



c) d d d a a 



and is discontinuous. Consequently, every group of this type is discon- 

 tinuous. 



In the table on pages 391-397, Vol. XXXV., of These Proceedings, 

 as mentioned above, I have marked by an asterisk those types of 

 structure for which all real groups are continuous ; and by a dagger 

 those types of structure for which I have found at least one real group 

 that is discontinuous. 



