METARGON (Plate XX, 5, 6 and 7) again shows only an additional seven atoms
in each arm.

METARGON: Six arms of 106 atoms 636
Central tetrahedra 120
----
Total 756
----
Atomic weight ----
Number weight 756/18 42
[Illustration: PLATE XXI.]

KRYPTON (Plate XXI, 1 and 4, and Plate XX, 6 and 7) contains the nitrogen
"balloon," elongated by its juxtaposition to _b_ 63. The central tetrahedra
appear as usual.

KRYPTON: Six arms of 224 atoms 1344
Central tetrahedra 120
-----
Total 1464
-----
Atomic weight 81.20
Number weight 1464/18 81.33
META-KRYPTON differs only from krypton by the substitution of _z_ for _y_
in each arm of the star.

META-KRYPTON: Six arms of 231 atoms 1386
Central tetrahedra 120
-----
Total 1506