"Fox-terriers are born with about four times as much original sin"

Montmorency is a fox-terrier, who accompanies the three on their Thames trip. At Marlow he gets involved with a cat, and Jerome typically digresses with an incident in London involving another fox-terrier and various other dogs, who caused a chaotic scene.

Fox terrier and kitten
Public DomainFox terrier and kitten - Credit: Prskavka, Wikimedia Commons