Schoenberg's Preliminary Exercises in Counterpoint

I just purchased this book and finished reading the first species section but I'm a bit at a loss as to what cantus firmus I should use. He doesn't seem to give any to practice on in the book but doesn't direct you to make up your own or use some from other texts. It seems like it wouldn't matter much but I'd hate to miss out on anything if I just started picking some randomly. Anyone familiar with this book?

Jeppeson's counterpoint book offers several cantus firmus to practice and examples- see pg 109 - 110 fopr the cantus firmus he uses. Also check Fux's book for cantus firmus and examples.

Dubois' book has many canti firmi in many modes/keys, and he also gives examples of "solved" counterpoints on the canti firmi. I haven't found an English translation of the book as of yet, though, but there's a French and Italian version for sure.

In general, you can use the canti firmi that Schoenberg uses in his examples (I haven't read the book, but I assume that he uses actual canti firmi as examples and doesn't make his own). Just take that cantus firmus and write your own counterpoint on top of it.

Counterpoint is generally a subject you need a teacher for (or someone else who knows counterpoint very well) so you can get feedback on the exercises, have them spot any mistakes you do and help you fix them, stuff like that.

The practice canti firmi that Schoenberg provides for pratice are at the very end of the chapter on first species (in my edition, it's on page 21, and listed as Ex. 9) It took me forever to find them! I think that you are supposed to use the same C.F.s to practice all of the species, since i there don't seem to be any listed in Chapter two as specifically for 2nd species practice, and so on.