[405] Some examples of the walled off ambulatory are found, however. See Enlart, I, p. 234, note 5.
[406] See Rivoira, I, p. 183, for dates of Santo Stefano and Ivrea.
[407] An annular tunnel vault also covered the passage around the tribune of the so-called stadium of Domitian already mentioned. See Rivoira, I, p. 184.
[408] For other examples, see Enlart, I, p. 266, note 6. A similar vault is sometimes found in the aisles of circular churches, as for example in Ste. Croix at Quimperlé (eleventh century). Baudot and Perrault-Dabot, II, pl. 5.
[409] See Rivoira, II, p. 289.
[410] At intervals this vault is cut by lunettes or groined bays but it is fundamentally an annular tunnel vault.
[411] Exactly as has been suggested in regard to similar side aisle vaults.
[412] See Enlart, I, p. 266, note 6.
[413] Enlart, I, p. 34, Fig. 14.
[414] Revoil, I, pl. XLVIII.