As in 1955, Carvin didn't offer any basses in 1956.  It had been 5 years since Leo introduced the Precision Bass, but Carvin hadn't gotten on board with this new instrument - but that would soon change.

1956 Guitars

1956 Guitar Amps

1956 Bass Amps

Also, Carvin no longer offered Fender products in 1956 - so if you wanted a P-Bass, you had to go somewhere else.