_Pl. XCII, 3 (MS. B, 56b) corresponds to a plan like the one in MS. B 35a, in which the niches would be visible outside or, as in the following sketch, with the addition of a niche in the middle of each chapel. Pl. XC, No. 6. The niches themselves are surrounded by smaller niches (see also No. 1 on the same plate). Octagon expanded on each side. A. by a square chapel: MS. B. 34b (not reproduced here). B. by a square with 3 niches: MS. B. 11b (see Pl. XCIV, No. 3). C. by octagonal chapels: a) MS. B, 21a; Pl. LXXXVIII, No. 4. b) No. 2 on the same plate. Underneath there is the remark:_ "quest'e come le 8 cappele ano a essere facte" _(this is how the eight chapels are to be executed). c) Pl. LXXXVIII, No. 5. Elevation to the plans on the same sheet, it is accompanied by the note:_ "ciasscuno de' 9 tiburi no'uole - passare l'alteza - di - 2 - quadri" _(neither of the 9 domes must exceed the height of two squares). d) Pl. LXXXVIII, No. 1. Inside of the same octagon. MS. B, 30a, and 34b; these are three repetitions of parts of the same plan with very slight variations. D. by a circular chapel: MS. B, 18a (see Fig. 1 on page 47) gives the plan of this arrangement in which the exterior is square on the ground floor with only four of the chapels projecting, as is explained in the next sketch. Pl. LXXXIX, MS. B, 17b. Elevation to the preceding plan sketched on the opposite side of the sheet, and also marked A. It is accompanied by the following remark, indicating the theoretical character of these studies:_ questo - edifitio - anchora - starebbe - bene affarlo dalla linja - _a_ - _b_ - _c_ - _d_ - insu. _("This edifice would also produce a good effect if only the part above the lines_ a b, c d, _were executed"). Pl. LXXXIV, No. 11. The exterior has the form of an octagon, but the chapels project partly beyond it. On the left side of the sketch they appear larger than on the right side. Pl. XC, No. 1, (MS. B, 25b); Repetition of Pl. LXXXIV, No. 11. Pl. XC, No. 2. Elevation to the plan No. 1, and also to No. 6 of the same sheet._ _E. By chapels formed by four niches: Pl. LXXXIV, No. 7 (the circular plan on the left below) shows this arrangement in which the central dome has become circular inside and might therefore be classed after this group. [Footnote 1: This plan and some others of this class remind us of the plan of the Mausoleum of Augustus as it is represented for instance by Durand. See_ Cab. des Estampes, Bibliotheque Nationale, Paris, Topographie de Rome, V, 6, 82._] The sketch on the right hand side gives most likely the elevation for the last named plan. F. By chapels of still richer combinations, which necessitate an octagon of larger dimensions: Pl. XCI, No. 2 (MS. Ash. 11. 8b) [Footnote 2: The note accompanying this plan is given under No. 754.]; on this plan the chapels themselves appear to be central buildings formed like the first type of the third group. Pl. LXXXVIII, No. 3.