English versus American mice :
Here are photos of three of my mice, two English and one American. They are not excellent examples of show quality mice, but they're good enough to illustrate differences between the two types. In my opinion the chocolate Tan English is much better than the Reverse Siamese, but still you can see some of the English traits in the Reverse Siamese.
American mice are the mice commonly found in America's pet shops or breeders. English mice are mice directly descended from mice bred in England to have this distinctive look. Different rodent clubs in America handle this issue in different ways. Some try to get their members to only show English mice while others judge them in separate classes.
Examples of an English mouse:
------- Ears --------
This is a chocolate Tan English. Note the size of his ears and their placement on his head. The ears in any show mouse ought to be free of wrinkles and symmetrically shaped and placed on the head.
This is one of my Americans. The ears are smaller and don't jut from the head at the same angle.
----- Tails ---------
Tails in English are to be longer than the body. Note how much longer the right hand mouse's tail is from the American on her left.
Another example of the length of an English's tail.
----- Body Type ------
These photos may not be the greatest examples, but the body is different in English mice. Put simply English have longer bodies. Even when she's scrunched-up (photo on right) you can see the English reverse siamese is bigger than her same-age American counterpart. The body shape is usually more streamlined in English, too. English mice on average are just bigger mice.