The James Branch Cabell Library at Virginia Commonwealth University produced a nice button with the couplet. (See also their website for further information.)And the name of the sulky beast is Cabell, in ironic consonance with rabble. I don't wonder you did not know, since I was forced to spend two years in New York under the alias of Cáy-bel and Cay-béll, through the utter impossibility of persuading any Northerner to pronounce my actual name. (Between Friends: Letters of James Branch Cabell and Others, p. 13)
Thanks to Bill Lloyd!