This novelty silver tortoise bell is a very rare model indeed. They were far more common in a smaller size, consequently larger bells like this are very rarely seen. The bell is operated by depressing the head or tail, releasing a wind-up clockwork mechanism.
Tortoise bells had their heyday in the late 19th / early 20th century. They came in two sizes made by a company who stamped the cast iron base GS. The basic model comes with a cast iron top and another with a faux tortoiseshell that is extremely rare due to the fragility of the material. Little is known about the makers besides some bells are stamped made in Germany. It is very possible that some were made in England too.
Clearly, tortoise bells were popular in Edwardian England, where ingenious silversmiths ran a good business swapping the cast iron shells for silver ones.
Nicholas Wells has handled many of the finest silver tortoise bells and can confirm that this is the first of this size that he has offered.