AND RETICULATIONS OF THE R-GON. 233 
reversion or symmetry, one perpendicular to the other. 
Of these three fractions two or all will be irreducible, and 
therefore to be accounted zeros. 
RY” (7, k+1) 
(47 =i Je a |-I (4 (k hus a aa |—1 ia 
Ay +2. yer—2) 111 ; ]R—#—k—-S) | 1 pe he 
el | 1 
(3(r-24)) *' | (Art. 8), 
eco? 
1 
where 2<t0, a<tr—2k-4, vpr-k-5. Here & is odd, 
and r and 2 both even. 
This is the number of r-gons partitioned by &+1 dia- 
gonals so as to have one agonal axis of reversion, and two 
marginal faces. 
R”™(r,k+1) 
=> GS EE EEL hee gk-A(r—2—2) , 
mitiist p02) 1 ; 3-#—-k-4) | 1 ji 
(Art. 9), where & is odd, r is odd, and 2 is even, 20, 
atr—2k-3, wpr-k-4. 
This is the number of r-gous partitioned by £+1 dia- 
gonals so as to have two marginal faces and a monogonal 
axis. 
R“(r,k+1)! 
(A(r—2) 1 (Ga) IA 2 
7 3,4 jie a ala tl Ad 
hyy 
_ Gr-24))P 
an 
1? 
where r, & and « are all even, #40, x<fr-2k-4, 
apr—-k—-4. 
This is the number of (4+2)-partitioned r-gons that 
have a drawn diagonal axis and two marginal faces. 
(Art. 10), 
