3, _Andantino_; the superfluous recurrence of the Principal theme begins in measure 19 from the end, after the regular sonatine-design has been achieved, fully, though concisely.
2.

ABBREVIATION OF THE REGULAR FORM .-- This consists chiefly in the omission of the Principal theme after the Development (that is, in beginning the Recapitulation with the Subordinate theme).

Other contractions, by omission of _portions_ (Parts) of important thematic members, during the Recapitulation, are also possible, but not so common.
An illustration of the omitted Principal theme may be found in Mendelssohn, Songs Without Words, No.

5:-- _Principal Theme_, period, extended (measures 1-11, dissolved into Transition--18).
_Subordinate Theme_, phrase, repeated and extended (19-28).

_Codetta_ (28-33).