The scene of the myth of Arion takes place in the centre of the Hall.
A cornice depicts on several registers a
marine thiasos
, one of the most recurrent themes in ancient iconography, especially reproduced in the mosaics of seascapes, images that refer to ideal landscapes, often present in other rooms of the Villa del Casale.
The marine procession is populated by
ichthyocentaurs
,
tritons
,
nereids
and an innumerable variety of sea and land animals, including some
cherubs
. 
The figure of
Arion
stands out in the centre of the composition, covered by a mantle, playing his cithara and riding a dolphin.
Above him are two flying cherubs stretching out a drape that continues on to the drapery of one of the nymphs lying on the rocks and listening to his music.
Other mythical beings, including a sea monster, animate the waters of this large marine painting, depicted with waves marked by straight or zigzag lines.
In the apse area, which can be assumed to have hosted the beds for the triclinium, there is a monumental figure of
Oceanus
, the father of all waters, surrounded by rich marine fauna reminiscent of numerous North African examples.
