Tomb 21 and tomb 20 are one of a kind. Tomb 21 can only
partly be seen from the Via Severiana.
Here too the inscription above the entrance is missing.
The burial chamber was meant for a mixed form of burial.
In contrast with tomb 20 a little bit more decoration
has been preserved.
In later time a second arcosolium has been created in the right
wall above the original one. The new one had a beautiful painting
(Ostia inv. nr. 10818).
On a yellow field three squares surrounded by red stripes were
painted. In the middle square was a Medusa-head.
The other squares depicted flowers. Also the top of the arcosolium
was decorated with paintings of birds and flowers. Beneath the
floor four formae were located.
On a piece of mosaic from the floor an inscription is to be noticed:
EXATI, probably a name. Tomb 21 must also be dated around 160-170