The reference is to the 15th Capital of the Ducal Palace. Series of Capitals of the Lower Arcade.
Notebook M2 p.102 ‘The 15th is the first that occurs. Its leafage is handled a good deal as that described of the Bon third order capitals: Its breast ribs ripple beautifully. All is exquisite in lobing & undulation: but it has a late look: though its flower band is pure.’
[Version 0.05: May 2008]