Fig. 1 on p. 56. (MS. B, 75a) shows the result of this treatment
adapted to a peculiar purpose about which we shall have to say a few
words later on.

Pl. XCV, No. 1, shows the same plan but with the addition of a short
nave. This plan seems to have been suggested by the general
arrangement of S. Sepolcro at Milan.

MS. B. 57b (see the sketch reproduced on p.51). By adding towers in
the four outer angles to the last named plan, we obtain a plan which
bears the general features of Bramante's plans for S. Peter's at
Rome. [Footnote 2: See_ Les projets primitifs _etc., Pl. 9-12.] (See
p. 51 Fig. 1.)

Group IV.

Domes rising from an octagonal base.

This system, developed according to two different schemes, has given
rise to two classes with many varieties.

In a) On each side of the octagon chapels of equal form are added.

In b) The chapels are dissimilar; those which terminate the
principal axes being different in form from those which are added on
the diagonal sides of the octagon.

a. First Class.

The Chapel_ "degli Angeli," _at Florence, built only to a height of