No. 2.] 



TEIAD SYSTEMS— WHITE, COLE, CUMMINGS. 



79 



Systems 1-26— Continued. 



No group. 



Systems 1-26— rontimied. 



No group. 



IV. NO TRIPLE TETRADS, BUT HEAD. 



V. NO TRIPLE TETRADS OR HEAD, BUT SEMIHEAD. 

 Systems 1-3— Continued. 



Group of order 3. 

 3. 3 4 7 3 5 8 3 6 13 3 9 14 3 10 12 3 11 15 



Group of order 3. 



VI. NO TRIPLE TETRADS, HEAD, OR SEMIHEAD. 



Systems 1-15— Continued. 



No group. 

 4. 3 4 8 3 5 9 



No group. 



5. 3 4 8 3 5 10 



No group. 



