Pl, LXXXV, No. 4, and p. 45, Fig. 3, a Greek cross, repeated p. 45,
Fig. 3, is another development of the square central plan.
The remainder of these studies show two different systems; in the first the dome rises from a square plan,—in the second from an octagonal base._
_Group III.
Domes rising from a square base and four pillars. [Footnote 1: The ancient chapel San Satiro, via del Falcone, Milan, is a specimen of this type.]_
a) First type. _A Dome resting on four pillars in the centre of a square edifice, with an apse in the middle, of each of the four sides. We have eleven variations of this type.
aa) Pl. LXXXVIII, No. 3.
bb) Pl. LXXX, No. 5.
cc) Pl. LXXXV, Nos. 2, 3, 5.
dd) Pl. LXXXIV, No. 1 and 4 beneath.
ee) Pl. LXXXV, Nos. 1, 7, 10, 11._