I am a clarinettist so I am a little embarrassed to need to ask this. I have not played the bass clarinet. I am looking at a miniature score of Stravinsky's The Rite of Spring (Dover Miniature Scores).
Towards the end of The Ritual Action of the Ancestors, there are two bass clarinets playing. The second part is written in the bass clef and the first switches to the bass clef at bar 143. I thought that the bass clarinet was a transposing instrument (down a major 9th) and would be written in the treble clef. As a player, how would I interpret the bass clef? Would I now consider my instrument as only transposing by a major second?
More generally, what notation is used for the bass clarinet?
Note that this question has been split. The original mention of the instrumentation is in a new question.