This is a ContraAlto, made by a German company called Mirafone. It is my understanding that this horn is in Eb, with an F crook. The ContraAlto is used often in German bands. There is another horn out there called a Wagner Tuba (not pictured) that looks just like this. Not sure of the differences. I have seen some horns like this in Bb also.
In the first three pictures, the fourth valve acts like the fourth valve on a Euphonium or Bass, and not that of a French horn.
The bottom picture of of a horn still manufactured by the AMATI instrument company that they call the Rotary Tenor Horn. It is in Eb and F.
The AMATI Rotory Tenor Horn. Sold under the brand name of 'V.F. Cerveny.