Good morning gentlemen
The sales description described it as two ox. It is interesting how we interpret what we see as at the time it seemed reasonable that the two beasts were ox. The mane in question looked like the ribs that are seen on work of ox in other pieces. See here for examples
http://www.militaria.co.za/nmb/topic/21344-bullbullsoxen-tsuba/?hl=oxen
However as Curran (who seems to have a very niche taste in manga ????) noted they are quite skinny for ox. On the other hand, I see a horn, but it could be an Edo period mop-top...
Also Franco points out a tail that might not be that of a horse.
All in all, with out having it in hand yet it seems that they are indeed horses which makes me wonder why they also appear to be two ox?
A play on a famous motif?
An obscure reference to something more profound?
A cheap knock off to fool the foolish?
Old Wilson looking for something that isn't there?
PS. I typed this before i read your post. Thank you Curran for looking up the signature