4, which see:--Part I extends from measure 2 to 9 (after 1 1/2 measures of recitative introduction); Part II, measures 10-13; Part III, measures 14-21; Part IV, measures 22-32; Part V, measures 33-40; codetta to end.

The Fourth Part bears very little resemblance to the Second, and assumes rather the character of a wholly independent Part.
GROUP OF PARTS .-- In some, comparatively rare, instances, the arrangement of perfect cadences is such that,--coupled with independence of melodic formation and character,--the composition seems to separate into _four or more individual sections_ or Parts, with or without a recurrence of the First one; or into three _different_ Parts, lacking the evidence of the return to the beginning.

When such irregularities are encountered, or when any conditions appear which elude or baffle natural classification among the Three-Part Song-forms (simple or enlarged), the piece may be called a group of Parts.

The use of this term is entirely legitimate, and is commended to the student on account of its convenience, for all examples of the Song-form which, _upon thoroughly conscientious analysis_, present confusing features, at variance with our adopted classification.

Of one thing only he must assure himself,--that the design is a _Song-form_ (_i.e._ an association of _Parts_), and not one of the larger forms to be explained in later chapters.