Codetta (I), as before, but slightly extended (175-187). The second codetta is omitted.

Coda, phrase, repeated and extended (188-200).

RELATION TO THE THREE-PART SONG-FORM.—In a former chapter (XIII) the Three-Part form was defined as the type of perfect structural design, upon which every larger (or higher) form is based. Nowhere is the connection more striking, and the process of natural evolution out of this germ more directly apparent, than in the sonata-allegro design. See the diagram on page 124. The Exposition corresponds to the First Part, so expanded as to comprise the two themes and codetta, fused into one larger division; the "statement" of a more comprehensive thematic group than the ordinary Part contains, but no more, for all that, than the usual initial "statement." The Development corresponds to the Second Part (proportionately expanded), and the Recapitulation to the Third Part, or recurrence and confirmation of the "statement."

Any Three-Part Song-form, the moment that its First Part expands and divides into the semblance of two fairly distinct thematic sections, becomes what might be called a miniature sonata-allegro form. Many Three-Part Song-forms are so broad, and many sonata-allegros so diminutive, that it is here again often difficult to determine the line of demarcation between them. Example 55 (cited because of its comparative brevity) is scarcely more than such a broadly expanded Three-Part Song-form. An example which approaches much more nearly the unmistakable Three-Part song, may be found in Mozart, sonata No. 12, Menuetto:—

Part I, section one (embryo of a principal theme), measures 1-10, period, extended; section two (embryo of a subordinate theme) measures 11-18, period, in different key.

Part II, group of three phrases, measures 19-30.

Part III, section one, as before, measures 31-40; section two, as before, but in the principal key, measures 41-48.

This is, of course, a Three-Part Song-form; but the essential features of the Sonata-allegro are unquestionably present, in miniature.

See also, Beethoven, sonata, op. 101, first movement; certainly a sonata-allegro design, but diminutive.