Dan Putnam recently purchased a small lot of shaves that included this particular example. He believes that it is some type of coach router, but despite searching he has been unable to find any other examples of this type.
Some distinctive features are:
The number "31" cast twice into body and once on the blade
Slots to the right and left of center possibly to hold a fence,
A very slightly convex sole,
"warranted annla..." cast on blade.
The tool itself is roughly 13" long.
Dan would be grateful for your help.