elerated by the use of
quicklime.

[Illustration: FIG. 2.--Section of Galleries at different levels. (From
Seroux d'Agincourt)]

[Illustration: FIG. 3.--View of a Gallery.]

[Illustration: FIG. 4.--Loculi. (From de Rossi.)]

[Illustration: FIGS. 5 and 6.--Loculi. (From de Rossi.)]

Interment in the wall-recess or _loculus_, though infinitely the most
common, was not the only mode employed in the catacombs. Other forms of
very frequent recurrence are the _table tomb_ and _arched tomb_, or
_arcosolium_. From the annexed woodcuts it will be seen that these only
differ in the form of the surmounting recess. In each case the arched
tomb was formed by an oblong chest, either hollowed out of the rock, or
built of masonry, and closed with a horizontal slab. But in the
table-tomb (fig. 8) the recess above, essential for the introduction of
the corpse, is square, while in the arcosolium (fig. 9), a form of later
date, it is semicircular. Sarcophagi are also found in the catacombs,
but are of rare occurrence. They chiefly occur in the earlier
cemeteries, and the costliness of their construction confined their use
to the wealthiest classes--e.g. in the cemetery of St Domitilla, herself
a member of the imperial house. Another unfrequent mode of interment was
in graves like those of modern times, dug in the floor of the galleries
(Marchi, _u.s._, tav. xxi. xxvi.). Table-tombs and arcosolia are by no
means rare in the corridors of the catacombs, but they belong more
generally to the _cubicula_, or family vaults, of which we now proceed
to speak.

[Illustration: FIG. 7.--Glass Bottles. (From Bosio.)]

These _cubicula_ are small apartments, seldom more than 12 ft. square,
usually rectangular, though sometimes circular or polygonal, opening out
of the main corridors. They are not unfrequently ranged regularly along
the sides of the galleries, the doors of entrance, as may be seen in a
previous illustration (fig. 3), following one another in as orderly
succession as the bedchamber doors in the passage of a modern house. The
roof is sometimes flat, but is more usually vaulted, and sometimes
rises into a cupola. Both the roof and the walls are almost universally
coated with stucco and covered with fresco paintings--in the earlier
works merely decorative, in the later always symbolical or historical.
Each side of the cubiculum, except that of the entrance, usually
contains a recessed tomb, either a table-tomb or an arcosolium. That