What is? BANJO

BANJO Kiln Furniture. A saggar with a particular shape. A bit like a banjo. Mainly for glost firing. Ideal for a double row of dottled muffins.

BANJO - you can see the shape of the banjo saggar
in this picture, bottom right

UPDATE - What is a MUFFIN?

Don't get confused!  An American Muffin is a small domed spongy cake made with eggs and baking powder. An English Muffin is leavened bread, beloved by the English aristocracy particularly in the early 20th Century and served in a Muffin Dish.

A Muffin Dish should not be confused with the Muffin which is a small pottery plate measuring 5 or 6 inches in diameter. So Banjos were for small pottery plates.

more here>