W. F. Harvey: The Beast With Five Fingers: The old box contained something still alive; something very malevolent and something very evil

A well off English bachelor receives a legacy from his uncle. This includes the uncle's very large library and a box containing something that used to belong to his uncle. The box has air holes in it. It is not a rat or other small mammal for his collection, but it is something still alive; something very malevolent and something very evil