[375] Although not originally planned for four-part vaults in the choir, its present arrangement illustrates the combination referred to.
[376] This is not a noticeable fault with sexpartite choir vaulting since the crowns of all the window cells form similar angles.
[377] Porter, II, p. 83, Fig. 176.
[378] In referring to chevet vaults, the terms three-celled, four-celled, etc., refer to the number of window panels or severies, while the terms four-part, five-part, etc., refer to the total number of severies in the vault, generally one more than the number of window cells.
[379] See also the five-part chevet in the cathedral of Saint Louis at Blois (Loire-et-Cher) which is, however, of much later date.
[380] This may explain the fact that the buttressing rib type of chevet persisted side by side with this fourth form.
[381] In St. Étienne this rib would seem to be an addition to the original chevet.
[382] Street, pl. XXV. op. p. 408.
[383] Bond, p. 63.
[384] This church has a rather exceptional chevet in that it is considerably more than a semicircle in plan.