Germany (possibly)
Unknown Luthier

Wood, ebony, metal 
ca. 1850-1920s
Length of body: 15.5 in
Strings – Lutes – Violin Family

Various mute or practice skeleton violins have been made since the 17^th century.  This skeleton violin dates from @ 1850-1920s.  As there is no sound box, this skeleton-shaped violin may have also been used as a muted violin for special acoustic affects in various compositions.  In particular, Leopold Mozart used the term “Brettgeige,” or “board violin,” to describe a muted violin. For many professional violinist the ‘mute’ or ‘practice skeleton violin’ was and still is used to practice techniques without disturbing the neighbors. 

Resource: https://www.metmuseum.org/art/collection/search/503511