BASE, AND ITS MODIFICATIONS. 133 



Class h. Solid angles of the base replaced by four 

 planes resting on the primary planes, and having their 

 edges parallel to the edges of the pyramids. 



Class i. Solid angles of the base replaced by four 

 planes inclining more on- the terminal edges than 

 modification h. 





Class k. Solid angles of the base replaced by four 

 planes inclining more on the edges of the base than 

 modification h. 



A series of double eight-sided pyramids might 

 result from class h y , and , analogous to those re- 

 sulting from class d, but more acute. 



