This may clearly be seen from a study of the apse of Saint Jacques at Antwerp (probably sixteenth century), where the vault is unusual in the omission of all the true radiating ribs (Plate II-r). As a matter of fact such ribs were no longer of value since they did not mark the intersection of two vault panels but merely lay along a surface which is almost precisely like a section of a half dome. The tiercerons are still important since they mark the intersection of the window lunettes and carry the weight of the vault down to the piers. They are therefore retained. Thus, while the absence of radiants in Saint Jacques might seem to make this vault structurally less correct than that of l’Épine in reality such is not the case. Once it became the custom to introduce extra ribs into the chevet, this portion of the church underwent the same treatment as the vault of the nave or choir. Thus in England, to cite only extreme cases of elaboration, the later Gothic produced such vaults as those of Tewkesbury Abbey (between 1325 and 1350),[388] in France, such pendant types as that of Saint Pierre at Caen (probably early sixteenth century), and in Germany such a choir and apse as that of Freiburg cathedral (late fifteenth century) (Fig. 72).[389] The last named is especially interesting as showing the low point reached in rib vaulting for its ribs have almost no function as supporting members, some of them being actually free from the vault panels and are merely used to form a decorative pattern upon a vault which would stand equally well were they entirely removed. Such chevets are, in many cases, clever examples of stone cutting and decorative design but they are lacking in fundamental structural character. THE NUMBER OF CHEVET CELLS [Illustration: FIG. 72.--FREIBURG, CATHEDRAL.]