A trip down memory lane of the history of calling cards and the impact it made on the social life is quite fascinating.  By the 1920's favor of fancy lithograph cards were replaced with a simple printed card for personal use.

This little black leatherette case, simple in design but dignified, holds the cards of Mary, Dorothy Daisy, and Helen Frances Nathan. I assume three sisters.  The paper covering on the inside of the case is a flower floral design. A stiffened part of this paper holds the cards into place when the case is opened.  

Size of the case is 2" wide x 3-3/4"long. Case has a slight curve, possibly from the cards.