Friedrich J. Lehmann

“ Cantus Firmus
LESSON IX FIFTH SPECIES: FLORID COUNTERPOINT
Florid counterpoint is a mixture of the second, third and fourth species.
In addition to these species eighth-notes may be used in groups of two on the second and fourth quarters of the measure. Both notes should be approached and left stepwise, with the exception that the first may be taken by a skip. [Fig. 79.]
Not more than one and one-half measures of any one species should be used continuously in one part. [Fig. 80.]
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In the use of quarter-notes it is necessary to exercise care. ”

“ When the counterpoint begins on the first quarter it must form a perfect consonance with the cantus firmus. When on the second or fourth quarter, any consonance may be used.
All previous rules are to be regarded, unless exceptions are made.
At least one of the first three quarter-notes of a measure should be left degreewise. [Fig. 43.]
The last quarter of a measure is usually left degreewise. If approached by a skip or by a degreewise progression of at least two quarter-notes, it may be left by a skip in the opposite direction from which it was approached. ”

“ When the counterpoint is below the cantus firmus, the fifth of the chord needs special treatment. It is permitted on the weak beat when the lower is treated as an harmonic passing-tone.
An harmonic passing-tone is the second of three tones belonging to the same chord. [Fig. 23a.] While the third tone should be a member of the chord containing the fifth as an harmonic passing-tone, the chord above it may change as in Fig. 23b.
The fifth is permitted on the strong beat when it is only an implied fifth (six-four chord) ”