DK„ J. CASEY ON CYCLIDES AND SPHEEO-QITARTICS. 
673 
2°. Cone whose vertex is a point on two lines of A : 
f*=4, k = 2, -j 
v=6, r — 1, l A Cartesian oval, sixth class. 
< = 9, § = 0. J 
3°. Cone whose vertex is a point on a line of 2 and which stands on the cuspidal 
edge of 2 : 
[jj= 12 , *= 37 , ^ 
v— 7, r— 2, > Evolute of circular cubic of sixth class. 
,= 2, §=37. J 
4°. Cone whose vertex is a point on two lines of 2 and which stands on the cuspidal 
edge of 2 : 
^= 12 , * = 18 , ^ 
v= 6, r= 9, > Evolute of Cartesian oval of sixth class. 
/= 0, §=36. J 
II. When U and V touch. 
1°. Cone whose vertex is a point of A : 
[Jj = o, * = 0, v 
i>=4, r=0, > A circular cubic of fourth class. 
i=3, §=1. J 
2°. Cone whose vertex is a point on two lines of A : 
f*= 4, *=2, 'j 
v=4, r=l, > A Cartesian oval of fourth class. 
;= 2 , §= 1 . J 
3°. Cone whose vertex is a point on a line of 2 and which stands on the cuspidal 
edge of 2 : 
f*=6, *=5, v 
f=5, Jr =4, > Evolute of circular cubic of fourth class. 
i=2, §=5. J 
4°. Cone whose vertex is a point on two lines of 2 and which stands on the cuspidal 
edge of 2 : 
II 
ccT 
II 
v=4, 
r=3, 
/=0, 
§=4. 
Evolute of Cartesian oval of fourth class. 
