[141] See Northcote’s Roma Sotterranea.
[142] Ibid.
[143] Ibid.
[144] Perret, Catacombes de Rome.
[145] Palmer’s Early Christian Symbolism.
[146] Northcote’s Roma Sotterranea.
[147] Palmer.
[148] Ibid.
[149] Dr. Northcote.
[150] Perret, Catacombes de Rome, vol. x.