I was using version 1.8.1 of Clozure downloaded from the Mac App store. On a hunch I downloaded the version from the Clozure website (ftp://clozure.com/pub/release/1.9/) and tried Slime again. Works perfectly!
The version from the Mac App store is the Clozure IDE, not the CLI application. I don't understand why that makes a difference but it does.
Helmut, thanks for your suggestions. Working from them led me to question my Clozure distribution.
Dana S. Wheeler dswheeler777.at.gmail.com