Highly collectable and hard to find, the Victorian Thornhill mouse.
 
I have had a pair of earrings before, and seen 4 rings go at Bonhams Hercules Collection which were thought to be Thornhill.
This is also not marked but thought to be Thornhill also. The chubby body and detailed modelling and features are distinctive.
He holds a natural pearl in his mouth.
Modelled in 18 carat gold.Circa 1880weight - 2.8g
mouse is 20mm long from tail to pearl
 
Now made into a pendant
 
Thornhill images courtesy of 'Jewellery In The Age Of Queen Victoria' by Charlotte Gere and Judy Rudore page 223