From Academic Kids
The sarrusophone is a transposing musical instrument invented by Pierre-Louis Gautrot in 1856 to compete with the saxophone as a replacement for the bassoon in bands. It was so similar to the saxophone that Adolphe Sax repeatedly filed lawsuits against Sarrus. It was named after the French bandmaster Pierre Auguste Sarrus (1813-1876).
It is made of metal, resembles an ophecleide  (http://www.nikknakks.net/Euphonium/Instruments/ophecleide.html) in shape, and is played with a double reed. Its fingering is similar to a saxophone, and it was made in sizes from sopranino to subcontrabass.
The sarrusophone is rarely called for in classical music. However, around the turn of the 20th century, the contrabass sarrusophone in E-flat enjoyed a vogue as a less physically fragile subsitute for the contrabassoon, so that it is called for in, for example, Maurice Ravel's L'heure espagnol (1907) and Arrigo Boito's Nerone (1924). These parts are nowadays often played on the contrabassoon.
The sarrusophone is now obsolete and only used as a novelty upon occasions. It had poor intonation and a sound less clear than that of the saxophone.