aisle of the church. The southern bay is separated from its
companion by a broad arch. It is an oblong chamber reduced to a figure
approaching a square by throwing broad arches across its ends and
setting back the wall arches from the cornice. This arrangement allows
the bay to be covered by a low drumless dome. Two openings, separated by
a pier, lead respectively to the nave and the southern aisle of the
church.

The interior of the church has undergone serious alterations since it
has become a mosque, but enough of the original building has survived to
show that the plan was that of an 'ambulatory church.'

Each side of the ambulatory is divided into three bays, covered with
cross-groined vaults whose springings to the central area correspond
exactly to the columns of such an arcade as that which occupies the west
dome bay of S. Andrew (p. 114). We may therefore safely assume that
triple arcades originally separated the ambulatory from the central area
and filled in the lower part of the dome arches. The tympana of these
arches above were pierced to north, south, and west by three windows now
built up but whose outlines are still visible beneath the whitewash
which has been daubed over them. The angles of the ambulatory are
covered by cross vaults.

The pointed arches at present opening from the ambulatory to the central
area were formed to make the church more suitable for Moslem worship, as
were those of the north church. In fact we have here a repetition of the
treatment of the Pammakaristos (p. 151), when converted into a mosque.
The use of cross-groined vaults in the ambulatory is a feature which
distinguishes this church from the other ambulatory churches of
Constantinople and connects it more closely with the domed-cross church.
The vaults in the northern portion of the ambulatory have been partially
defaced in the course of Turkish repairs.

[Illustration: PLATE XXXIV.
(1) S. MARY PANACHRANTOS. EAST WINDOW OF THE SOUTH CHURCH.
(2) S. MARY PANACHRANTOS. THE OUTER NARTHEX, LOOKING SOUTH.
_To face page 130._]

The central apse is lighted by a large triple window. It is covered by
a cross-groined vault and has on each side a tall shallow segmental
niche whose head rises above the springing cornice. Below this the
niches have been much hacked away. The passages leading to the lateral
chapels are remarkably low, not more than 1.90 m. high to the crown of
the arch.

The southern chapel is similar to t